4chan handles this perfectly, but it comes with a general unpoliteness and freedom that most people don't like. However, those aspects of it are exactly what keeps the community fresh and constantly re-inventing itself, because you need cultural artifacts (memes, ways of interacting, etc) to be generated that oppose whatever the prevailing narrative is, and those are harder to be generated if everyone has to be polite all the time.
So the solution is fairly simple: remove upvotes so the conventionally-minded can't decide on what's being discussed, and don't moderate based on politeness, but on subject. 4chan has lots of moderation, but it's mostly focused around which board the discussion should go in, i.e. if you want to talk politics go to the politics board, don't do it in the video games one or your thread will be deleted. This is obviously a solution that doesn't work for most people, but that's the price you have to pay if you want actual independent-mindedness in a community.