I guess the only true way to be certain of things in the federated world is to run your own instance and connect to other instances. Ultimately I do plan to do this with a few things, primarily moving myself off Mastodon.social and onto my own self-install on my own domain, the goal being that I’d have no other users beyond accounts for each of my music monikers and a ‘personal’ one. I’d love to have a books.mydomain.com instance of BookWyrm too if I can muster the enthusiasm to set it up.