I have a question, where are you seeing all this toxic behaviour in the first place? I don't think I've seen anyone interact with me in the open world beyond /wave in years. I admit I do 99% of my M+ gameplay with guildies and obviously all of my raiding with a guild. I assume that means this is happening in PUGs if that's the case, join a guild?
I mean you know if you're playing badly and no one says anything they're just laughing/raging at you on discord right? Not typing things doesn't make a community 'less toxic' it just makes a community silent.
EDIT: As I said previously WoW has a huge advantage over other online games that almost none of it's content is lobby based if you don't want it to be. If you guys think WoW is toxic because someone dabbs on you in a M+ 5 I would recommend steering clear of mobas and fps.