Just a thought I had since this constant flaming, toxicity in-game chat, and just let people chat before and after the match.
Can you simply just disable chat in-game and just go for pings?
This would help alot to decrease the constant harassment players get, among myself. I know there is a mute function, but that doesn't stop the harasser to keep on writing and ignoring the game and actually play.
Played LoL now for about 9 years on and off, and ever since around Season 2 there have been getting worse and worse.
IMO this part of the community ruins many games that could have been really enjoyable and fun hours to spend with friends and maybe even create new friends.
Just overall, chatting in-game takes away the fun, 8/10 times.