In light of "X" I finally committed to a Mastodon account (https://zirk.us/@brilokuloj). The instance seems perfect for me: art-focused but not topic-enforced, no required content warnings, self-promotion OK, bots allowed, Threads will be shadowbanned, etc. It's "academic" so probably a bit pretentious, but I'm pretentious, I can deal.
I still don't like Twitter or anything imitating it, so who knows if I'll use it much, but it's nice to be able to follow accounts of people who are mainly or exclusively on there. Staying to less fandom-oriented instances also gives me the impression it's less emotionally manipulative than Twitter. Maybe I can find a Mastodon reader that meets my needs; I have never benefited from seeing people's followers or following, for example.