visualization should improve automatically, when you read chess books and play over annotated games. you can maybe speed it up a little by using a board with no coordinates for your training and/or using a visualization trainer. I have "chess eye" as android app - think there's a pc version as well. but it will be a slow process even with training.
Chess coordinate system difficulties

It's like reading music - all a confusing pattern of dots and lines to begin with, along with incomprehensible Italian words. The more you practise the easier it gets - and if you don't, it won't.

Drill and drill.
Is it a coincidence that the moves you found 'confusing' are also quite bad moves? :-) There's no point in Bb4 in your example, as it is just helping white develop and control the center with tempo - c3, d4, even Bd2.
Also Qf6 puts her out there as a target, not to mention blocking the N from his best square at f6, and doing nothing about either central control or king safety (preparation of castling in what will become soon an open game!)
A strong player only needs a couple of such moves from you, to prepare an opening crush. I can't tell you how many games I win in 13 or 17 moves, because of such opening play - even against strong opponents.
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About coordinates being hard to memorize - no. I could play very convincing blindfold games also when I was not stronger than you are right now (I was then maybe at around 1300 FIDE or so). For some people it just comes easier. But you should be able to master it eventually. Keep drilling. It will come.

First of all, you're not alone. Everyone must learn the coordinates at some point.
The good news for you since you're a diamond members is...
IM Rensch has an excellent diamond member video series created to fix this exact issue, so I'd recommend going through the video archives and search for the board visualization training.
(It may be categorized with the blindfold chess training video if you have trouble finding it on the first go.)
Here is something very basic that should help you too.
Remember the bottom right square should always be white. (Bottom right rhymes with white).
So following that logic, say you have the white pieces. Since you know the far right square is h1 and you know it's white, then g1 must be black since the colors alternate every other square. And, of course, f1 must be white, e1 (where the king starts) is black, d1 (queen always starts on her own color) is white, c1 is black, b1 is white and a1 is black.
Okay, so now you have all the files and the colors of their squares sorted.
Onward...
You're now ready for the ranks!
Since you know a1 is black and each square vertically also alternates in color just like horizontally, then a2 must be white.
(So a3 must be black, a4 white, a5 black, a6 white, a7 black and a8 is white.)
But what else have we noticed?
All the odd squares on the "a" file are black and all the even squares on the a file are white.
So since the "b" file is the next one and the squares must alternate in color, then you now know all the odd squares on the b file are white and all the even b file squares are black.
And so the "c" file must be like the 'a' file and the "d" file must be like the "b" file.
So let's do a real life practical over the board test.
Say you develop your light square bishop to the c4 square and then form a battery with your queen on the b3 square.
So you have Bc4 and Qb3.
Well you know according to the rules we just learned, you know c4 must be a white square since it's on the 'c' file and it's on the 4th rank because it's an even numbered rank instead of odd.
And you know since they alternate, b3 must be white since it's on the third rank (odd) of the b file.
And sure enough, you look and they are the exact color.
Besides, you also know the light square bishop must naturally be on a light square.
Another quickie:
The queen always wears a matching dress to start the game.
So if she's the Queen of the black pieces, she will be on a black square (d8).
If she's the Queen of the white pieces, she will be on a white square (d1).
There are plenty of other neat little tricks to make the board smaller for you and pretty soon someone can call out a square to you and you'll know what color it is.
Break it down into manageable, bite-size chunks at first using those rules.
Then try to remember some of the most common moves you make, like, just as an example,
1.e4 2.Nf3
Or with black
1...c5 2...d6
Try to remember what the board and pieces look like for as many moves in your opening and games as you can.
Then try to add one more move.
Work it like a muscle gradually adding more until you can memorize your first entire game like you're a human PGN.
Then when you're mowing the lawn you can see the board and pieces and play through as many games as you like in your mind's eye until you're done.

It can be quite embarressing. Sometimes when someone tells me to move a piece to h6 for example I freeze up or worse still move to the wrong square and they look at me like I'm an idiot.
I wonder if a better system would be to divide the board into quadrants A,B,C,D. And subquadrants q,x,y,z, then numbers 1-4.
So Ax2 would be a3 for example.

No need to reinvent the wheel. Just follow post 5 and you'll know where every square on the board is without any confusion.

Here's a good way to remember the coordinates.
There are 8 squares across. You have 10 fingers. If you stick a thumb in each of your ears and leave the other fingers pointing up, the left hand is ABCD and the right hand is EFGH, if the bottom white corner is on the bottom right, the bottom left is on the bottom left, the top left is on the top left and the top right is on the top right, and of course the 4 middle squares are in the center.
Your two index fingers are the King and Queen. You can draw faces on them to help you remember. Some people think it helps to pretend your index fingers are making love or kissing, but this just makes the opponent just think you are extremely weird and work harder to checkmate you. Still others put on finger shadow puppet shows for their friends. None of this helps. Simple is best.
Another approach involves just remembering the friggin' squares! Lazy bastards! I mean, how hard is it really? Just spend a day or two thinking about it and practicing and you'll be saying E7# with the best of them.

For example when re-playing your game the computer barks out some long sequence "e6 h3 b5 j2" etc. At this point my head goes into meltdown.
You're not alone in that. Moves to J2 always leave me perplexed too. I wonder, hmmm.... he took his piece off the board - is he sacrificing it, resigning; what the hell?

First of all, you're not alone. Everyone must learn the coordinates at some point.
The good news for you since you're a diamond members is...
IM Rensch has an excellent diamond member video series created to fix this exact issue, so I'd recommend going through the video archives and search for the board visualization training.
(It may be categorized with the blindfold chess training video if you have trouble finding it on the first go.)
Here is something very basic that should help you too.
Remember the bottom right square should always be white. (Bottom right rhymes with white).
So following that logic, say you have the white pieces. Since you know the far right square is h1 and you know it's white, then g1 must be black since the colors alternate every other square. And, of course, f1 must be white, e1 (where the king starts) is black, d1 (queen always starts on her own color) is white, c1 is black, b1 is white and a1 is black.
Okay, so now you have all the files and the colors of their squares sorted.
Onward...
You're now ready for the ranks!
Since you know a1 is black and each square vertically also alternates in color just like horizontally, then a2 must be white.
(So a3 must be black, a4 white, a5 black, a6 white, a7 black and a8 is white.)
But what else have we noticed?
All the odd squares on the "a" file are black and all the even squares on the a file are white.
So since the "b" file is the next one and the squares must alternate in color, then you now know all the odd squares on the b file are white and all the even b file squares are black.
And so the "c" file must be like the 'a' file and the "d" file must be like the "b" file.
So let's do a real life practical over the board test.
Say you develop your light square bishop to the c4 square and then form a battery with your queen on the b3 square.
So you have Bc4 and Qb3.
Well you know according to the rules we just learned, you know c4 must be a white square since it's on the 'c' file and it's on the 4th rank because it's an even numbered rank instead of odd.
And you know since they alternate, b3 must be white since it's on the third rank (odd) of the b file.
And sure enough, you look and they are the exact color.
Besides, you also know the light square bishop must naturally be on a light square.
Another quickie:
The queen always wears a matching dress to start the game.
So if she's the Queen of the black pieces, she will be on a black square (d8).
If she's the Queen of the white pieces, she will be on a white square (d1).
There are plenty of other neat little tricks to make the board smaller for you and pretty soon someone can call out a square to you and you'll know what color it is.
Break it down into manageable, bite-size chunks at first using those rules.
Then try to remember some of the most common moves you make, like, just as an example,
1.e4 2.Nf3
Or with black
1...c5 2...d6
Try to remember what the board and pieces look like for as many moves in your opening and games as you can.
Then try to add one more move.
Work it like a muscle gradually adding more until you can memorize your first entire game like you're a human PGN.
Then when you're mowing the lawn you can see the board and pieces and play through as many games as you like in your mind's eye until you're done.
I'm sorry but this system is far too complex, I gave up trying to understand it halfway through. There must be a simpler way of remembering.
I need a real simple system so I had an idea:
ABCDEFG = A-Big-Crocodile-Does-Eat-Fat-Greasy-Homeless.
1: Bun, 2: Shoe, 3: Pea 4: Door, 5: Apple, 6: Bricks, 7: Heaven, 8: Crate
So C8 could be Crocodile Crate. As everything is a picture combo upside down doesn't matter. You just visualise each row and column with a picture. Idk.

First of all, you're not alone. Everyone must learn the coordinates at some point.
The good news for you since you're a diamond members is...
IM Rensch has an excellent diamond member video series created to fix this exact issue, so I'd recommend going through the video archives and search for the board visualization training.
(It may be categorized with the blindfold chess training video if you have trouble finding it on the first go.)
Here is something very basic that should help you too.
Remember the bottom right square should always be white. (Bottom right rhymes with white).
So following that logic, say you have the white pieces. Since you know the far right square is h1 and you know it's white, then g1 must be black since the colors alternate every other square. And, of course, f1 must be white, e1 (where the king starts) is black, d1 (queen always starts on her own color) is white, c1 is black, b1 is white and a1 is black.
Okay, so now you have all the files and the colors of their squares sorted.
Onward...
You're now ready for the ranks!
Since you know a1 is black and each square vertically also alternates in color just like horizontally, then a2 must be white.
(So a3 must be black, a4 white, a5 black, a6 white, a7 black and a8 is white.)
But what else have we noticed?
All the odd squares on the "a" file are black and all the even squares on the a file are white.
So since the "b" file is the next one and the squares must alternate in color, then you now know all the odd squares on the b file are white and all the even b file squares are black.
And so the "c" file must be like the 'a' file and the "d" file must be like the "b" file.
So let's do a real life practical over the board test.
Say you develop your light square bishop to the c4 square and then form a battery with your queen on the b3 square.
So you have Bc4 and Qb3.
Well you know according to the rules we just learned, you know c4 must be a white square since it's on the 'c' file and it's on the 4th rank because it's an even numbered rank instead of odd.
And you know since they alternate, b3 must be white since it's on the third rank (odd) of the b file.
And sure enough, you look and they are the exact color.
Besides, you also know the light square bishop must naturally be on a light square.
Another quickie:
The queen always wears a matching dress to start the game.
So if she's the Queen of the black pieces, she will be on a black square (d8).
If she's the Queen of the white pieces, she will be on a white square (d1).
There are plenty of other neat little tricks to make the board smaller for you and pretty soon someone can call out a square to you and you'll know what color it is.
Break it down into manageable, bite-size chunks at first using those rules.
Then try to remember some of the most common moves you make, like, just as an example,
1.e4 2.Nf3
Or with black
1...c5 2...d6
Try to remember what the board and pieces look like for as many moves in your opening and games as you can.
Then try to add one more move.
Work it like a muscle gradually adding more until you can memorize your first entire game like you're a human PGN.
Then when you're mowing the lawn you can see the board and pieces and play through as many games as you like in your mind's eye until you're done.
I'm sorry but this system is far too complex, I gave up trying to understand it halfway through. There must be a simpler way of remembering.
I need a real simple system so I had an idea:
ABCDEFG = A-Big-Crocodile-Does-Eat-Fat-Greasy-Homeless.
1: Bun, 2: Shoe, 3: Pea 4: Door, 5: Apple, 6: Bricks, 7: Heaven, 8: Crate
So C8 could be Crocodile Crate. As everything is a picture combo upside down doesn't matter. You just visualise each row and column with a picture. Idk.
Well it worked for me and seeing how it's either dark or light, odd or even, it's about as simple as it gets. Of course there are four different learning styles, so your approach with the inventing pictures and combos may work easier for you, but for me, complicating it with anything more than the bare essentials I provided in post 5 would only make it more complicated.
All the best on your quest though even still, as the important thing is you have the desire to improve and those who do, usually find a way to make it happen that works for them. Crocodile crates do seem interesting though lol. You should assign that one to the j2 you were talking about.

Here's how I do it. First quadrant (there are 4 in a clockwise direction), here is the basic "tank" pattern:
Focus just on the dark squares, the corner squares are the treads of the tank, the top dark square is the "turret." I found this pattern is easy to hold in my mind. The fourth file is a little problematic, but I solved in this way:
The corner dark square is another turrent, the corner turret, and the middle right square is another one. Took me a little while to be able to see this in my mind's eye, but now I've got it solid. Then associate the rows with the ranks and files. You have to do with with both sides, black and white. It takes some practice, but it works. The eventual goal is to see all four quadrants at once. Still a little fuzzy for me, but I'm getting there. Playing a lot of games helps, and seeing the moves in your mind first, and saying the moves outloud reenforces it.

Here's how I do it. First quadrant (there are 4 in a clockwise direction), here is the basic "tank" pattern:
Focus just on the dark squares, the corner squares are the treads of the tank, the top dark square is the "turret." I found this pattern is easy to hold in my mind. The fourth file is a little problematic, but I solved in this way:
The corner dark square is another turrent, the corner turret, and the middle right square is another one. Took me a little while to be able to see this in my mind's eye, but now I've got it solid. Then associate the rows with the ranks and files. You have to do with with both sides, black and white. It takes some practice, but it works. The eventual goal is to see all four quadrants at once. Still a little fuzzy for me, but I'm getting there. Playing a lot of games helps, and seeing the moves in your mind first, and saying the moves outloud reenforces it.
I like this idea because its visual but I'm having a hard time seeing the "tank", can you draw it out, along with numbering the quadrants? Thanks.

I'm sorry but this system is far too complex, I gave up trying to understand it halfway through. There must be a simpler way of remembering.
I need a real simple system so I had an idea:
ABCDEFG = A-Big-Crocodile-Does-Eat-Fat-Greasy-Homeless.
1: Bun, 2: Shoe, 3: Pea 4: Door, 5: Apple, 6: Bricks, 7: Heaven, 8: Crate
So C8 could be Crocodile Crate. As everything is a picture combo upside down doesn't matter. You just visualise each row and column with a picture. Idk.
Given the context, I'm having trouble pronouncing "5"
Hi...if you are like me you will have experienced difficulty with chess coordinates.
For example when re-playing your game the computer barks out some long sequence "e6 h3 b5 j2" etc. At this point my head goes into meltdown.
I have a very very hard time visualising where the square coordinates are on the board unless I have the numbers and letters written on each side of the board.
My chess teacher might say "move your knight to f5" and it will take me 30 seconds to figure out what that square is. I find this more confusing when I play as black. (I count 1-8 backwards and a-g backwards, sometimes forgetting which side is which).
What I am wondering is how more advanced players visualise where things are. Are there are tips to help? Does it ever get any easier? Or perhaps we are all in the same boat and you want to sympathise with me.
An example.