This is a short story, I'm also on my smurf atm that I'm playing on for fun. (Yeah, Master Yi tryharding) jk.
Anyway, the answer is simple. /mute all when you get in game.
It makes everything so better, you also feel better and more relaxed, not having to deal with people in chat. And of course, not knowing what they can say. No one can annoy you either!
And I've also practiced not to say anything in chat if I get mad at someone for example taking my jungle. You just simply have to hold back, I can now do it pretty easily. If you can't do that at all, I'm sorry I can't help. My only advice is the /mute all then.
Anyway thank you for reading and I hope this helps you :).