Curate.

Block liberally. Especially block any community that is focused around making fun of something - even if it’s a thing that deserves scorn, the vibe will grind you down, over time, especially if there are many communities like it. Block users who are assholes, after reporting them if it’s bad enough.

Subscribe/follow/equivalent-action things you are genuinely interested in; cut out the really general categories unless you actively enjoy browsing that topic. Smaller communities are usually better, if they have enough content to be alive.

If you have any sort of hobby, try joining a space about it. If it’s too toxic, block it, but if not, it is a good place to destress and perhaps even make friends.

Curate, it can’t be overstated enough. A lot of sites don’t let you sufficiently curate your feed, and if they don’t, you should leave em.