All of that is normal.
I remember one time, many years ago, I was maybe 1500 OTB, and I had a daily game.
I set up the position on a real board on my desk to study the position. I probably calculated for 10 minutes, finally chose my move, and then turned to my computer and I made the move... and suddenly I see I missed my opponent has a simple back rank mate in 2 moves!
That's an extreme example of chess blindness, but something like that happens to everyone.
Most people will have many stories for every one of the 8 things you mention.
---
As for chess seeming too big, I think websites like chess.com have information overload for new players. All you really need is 1 or 2 good books. I recommend 1 book on tactics, and 1 book on something else (endgames, strategy, or an annotated game collection).
You don't need to watch 1000 videos, or learn 1000 openings. The universe of chess is big, and it does take many years to improve, but there are also ideas that apply to all sorts of positions. There are only one dozen (or so) primary pawn structures in all of chess for example, and knowing these will give you the basic strategic road map in (basically) every opening you ever play. Reading a book of annotated games may seem at first like highly specific positions and idea, but many of those ideas will apply to all sorts of positions. As a simple example maybe Capablanca wins a game because of a strong knight on an outpost square. That's not just something you'll see in that game, or that opening, that's something you can start to think about looking for in all your games.
---
Anyway, good luck with your chess. If you play a little and learn a little every day, it slowly builds up. If you can improve 50-100 points a year I think that's a very respectable rate considering you have young family, so don't worry if you spend months and months seemingly not improving. Just have fun and keep playing.
I have been playing chess now and then since I was a kid, but I have only really tried to get better since this year. And although learning is a lot of fun, it also comes with a lot of frustrations. I am writing these because I am curious if you guys have the same frustrations, and also if you have any answers to it.
1. A lot of times I play a move in a game, and just after playing it, I see what the better move was. This also happens when I have really taken the time for the move.
2. I learned openings, but I forget them. This also happens when I learn the theory. In my case the only way I seem to remember the openings is to play them a lot of times.
3. When I have played a game I am mostly to lazy (tired) to study the game myself, so I use computer analysis. When I do study it myself I don't find nearly all the good moves as when I use computer analysis (I think I have found a good move, but then the computer analysis shows me wrong).
4. When I take the lessons on chess.com, a lot of time there is a lot of chess annotation for move sequences. I find it very difficult to picture the annotation and because of this I skip them, or I do study them, but a lesson then takes a lot of time (and there are sooooooo many lessons).
5. When I take lessons I am amazed by the amount of calculation that is sometimes needed. I can look 2, 3 or maybe 4 moves ahead (with mistakes now and then), but in the endgames you sometimes have to look 7 moves ahead. 7 moves ahead with all the possible variations seems impossible to me.
6. Reading chess annotation is hard. This is especially hard when you have the black position. First I have to think which box is meant with annotation, then I have to picture the chess piece. And from there you have to picture all kind of moves. This is difficult.
7. There are so many openings, so many tactics and so many variations, so many articles, so many movies, it seems like the universe of chess is too big to comprehend.
8. Last of all: I am a father of a 1 year old child and chess is a hobby next to my job and my other million obligations. Most of the time I am too tired to think well and play or learn well. I try to use spare time to study chess, but sometimes I wonder why I use my time for this, since my learning curve is just not so steep.
In the end I still love the game and love thinking of good moves. Of course I will keep playing the game, but I am curious if you guys run into the same stuff.