Best answer I’ve ever had for this was ‘find something to support.’ It can be anything. Just find a space where you have people trying to do something for the benefit of others with some bare minimum cost of entry. The group coming from people trying to help others will bias it toward nicer people. The cost of entry, even something small like $5/mo or physically present volunteering, deters anonymous trolling.

The other good option is classes. Doing things to improve your skills in something is generally worthwhile anyway, but it also puts you in contact with other people who share an interest.