Diamond V is completely saturated with toxic Chinese players

They're in almost every single game, and that's not an exaggeration. They level/buy a level 30 account and then go through their promos duo'd with a real Diamond+ account, so their final MMR puts them around Platinum I, and they only need a small number of games to get to Diamond V.

They clearly don't care about being banned, considering how consistently and blatantly toxic they are.

Is anything even being done to address this? It's kind of sad that this has been left unchecked to the point that it's now something you expect to see going into every game.