You should be able to filter it on the backend, if you go to the settings page on your instances website there should be a checkbox to toggle nsfw content.

I miss the golden days of the surreal memes subreddit, when it was funny like this

I'd rather have multiple small communities than monolithic ones in most cases personally, that and it avoids the reddit problem of being forced to use a subreddit despite bad/creepy mods cause you can just make your own version in another instance

It already has, I can't look for character art for my d&d campaign without 90% of the results being garbage AI generations

This might be against the grain but as an avid overwatch player I don't think overwatch needs to be inundated with content to stay alive, I think it'd be far healthier for them to make the existing content enjoyable. They have enough heroes, they have enough maps. They should be polishing those heroes and maps (which they did do this season, the changes to watchpoint are really good but the map was already really good, they need to focus on fixing things that are terrible lol).