And add also... "You played very well... You are a super Chess player".
Is it rude to say gg before giving mate

I once played with a few morons(before I shutted down the chat entirely). One of them sent me a gg after I lost a bishop at middlegame and then insisted that I will embarass myself by playing anymore that game and another one who gave me a link where I can find books on chess to learn, like he was some kind of master. Just don't bother having a chat open.

I like to say gg but when I do my opponent wouldn't even see my message because there in another game most likely so I do it before the game ends so they would see it.Is this considered runde or unsportsmanlike?Please tell me
Before check-mating your opponent.... say "I am sorry".
It would be polite.
I've done that if they outplayed me and blundered. Or I've told them they outplayed me.
I think it's fine to say 'gg' before checkmating in the endgame. Any other time seems kinda sarcastic.

I once played with a few morons(before I shutted down the chat entirely). One of them sent me a gg after I lost a bishop at middlegame and then insisted that I will embarass myself by playing anymore that game and another one who gave me a link where I can find books on chess to learn, like he was some kind of master. Just don't bother having a chat open.
Man, you should thank that your opponent because he cares about your Chess education.

I find something like "oh uh gg" or something like that not that rude but just saying a plain gg before finishing the game sounds rude

I once played with a few morons(before I shutted down the chat entirely). One of them sent me a gg after I lost a bishop at middlegame and then insisted that I will embarass myself by playing anymore that game and another one who gave me a link where I can find books on chess to learn, like he was some kind of master. Just don't bother having a chat open.
Man, you should thank that your opponent because he cares about your Chess education.
It was just a soft way towards sarcasm, maybe like your own comment... 😂
Do they believe that I cannot search online for resources, even on chess.com?

I mostly just say gg if I lose or if my opponent says gg. Some people do not feel friendly after they lose.

It depends. If it's a good game, then it's ok to say gg at any point. If it's not a good game, then there is no point in saying it, other than to be polite and recognize the opponents efforts.
I don't see any reason why it would be rude to say gg before checkmate. Knowing (or not knowing) a checkmate is coming shouldnt make any difference.
There have been many times I've said "this is a good game" or "good game" by move 20 or so, even if the game lasts another 40 moves. Win, lose, or draw, I'm just complimenting my opponent on how well they are doing.

I like to say gg but when I do my opponent wouldn't even see my message because there in another game most likely so I do it before the game ends so they would see it.Is this considered runde or unsportsmanlike?Please tell me
Only in online chess is typing good game and good luck considered "rude".
Do what is right, and be a good sport. You cant control how people take it. And also realize that people can and do act differently online simply because no one can see them.
A lot of wilting flowers live here.

It depends. If it's a good game, then it's ok to say gg at any point. If it's not a good game, then there is no point in saying it, other than to be polite and recognize the opponents efforts.
I don't see any reason why it would be rude to say gg before checkmate. Knowing (or not knowing) a checkmate is coming shouldnt make any difference.
There have been many times I've said "this is a good game" or "good game" by move 20 or so, even if the game lasts another 40 moves. Win, lose, or draw, I'm just complimenting my opponent on how well they are doing.
Talking of chess, I just got an exercise bicycle and I'm quite enjoying it. It doesn't lend itself to thinking about chess moves and I don't have music set up near it. I just did a couple of 20 minute stints and then took a walk in the cool air to my other house and listened to the Fourth Brandenburg Concerto, JS Bach, from a 50 year old vinyl by the Virtuosi of England. It's a few years since I played it and I realised that I was hearing it somewhat differently. Perhaps the first time with this deck, amp and speakers combination. In particular, I realised that, all this time, for nearly 50 years, I'd underestimated the magnificent 3rd movement. I think I thought I was a moon of a planet out there somewhere, listening to all the fugues with my mouth open and, at the finale, there were tears of joy. On that record, the Fourth is followed by the first movement of the Fifth, the Harpsichord Concerto, one of my favourite pieces of music of all time. I actually swiched that off before it started!
Now back on the exercise bike for another 20 mins and then a shower. I realised I hadn't written to you for a while! One day, I may be good enough for a game of chess with you!

Is typing "gg" at all polite? Why not type it out: "Good game". That in its own shows more respect than gg.

And only if I was going to win.

I usually say good games (ggs) after, but I have said it before the mate, I mean I often offer a draw if they are humble and polite about it.

Is typing "gg" at all polite? Why not type it out: "Good game". That in its own shows more respect than gg.
gc
I like to say gg but when I do my opponent wouldn't even see my message because there in another game most likely so I do it before the game ends so they would see it.Is this considered runde or unsportsmanlike?Please tell me
Before check-mating your opponent.... say "I am sorry".
It would be polite.