Oh definitely Mastodon. I’m having a blast over there, tons of fun people. Plus, the fact you can follow hashtags makes it super, super easy to populate your timeline with interesting content and then if it’s too much, you can pick a few people you like who are interested in that topic and just start following them instead, which gradually translates into a very organic feeling timeline without a long period of crickets while you look for friends and make new friends.
From what I’m hearing doomscrolling is quite difficult to achieve on mastodon. People are mostly horribly nice and supportive and stuff. And there’s no cool vampire algorithm exploiting heightened emotions. But where there’s a will, there’s a way! You can do it. Choose your doom-y hashtags carefully, my friend! We believe in you.