Don't play this game. It's addicitve, and once you try to taket things more seriously and try ranked games, you will experinece the worst of the worst. Riot does absolutely nothing to create fair match-ups, the most toxic and vile players are always on your team, and there's no way you can play a competitive match without having your stress levels go over the roof.
The game in itself is good, but it's in extremely bad shape due to the bad community and the bad teammates. EUNE is where society goes to die. We don't need chat restriction and chat bans, we need better matchmakers and better teammates. It's never about being hurt by chat, it's always about bad sportsmanship, a lack of willingness to cooperate, and a messed up attitude towards the team and the objectives. As long as money is the only thing that matters for Riot, this game will never be good.
It is indeed the most played MOBA out there, but more than half of the playerbase is stuck with playing this game due to Stockholm syndrome. Don't play it, don't get addicted, and don't get invested. I've been here on and off since S4 (2014), and it never got any better.