I'm still getting a feel for how all of this works together, so I haven't bothered blocking any communities yet. Were you just seeing those while browsing Local/All? I tend to stick to Subscribed unless I'm going adventuring for new stuff.

I have blocked like 6 meme shitposting comms, because it was annoying as shit

I feel your pain. lmao. I haven't blocked any, though. But during the beans shitposting period I almost blocked a few.