Being federated is basically your instance agreeing to show posts and users of another instance. I would be really surprised if dormi.zone was defederated since it seems like a pretty normal instance, lemmygrad would make more sense but it’s so popular I don’t think many instances have defederated them either. It’s probably just a bug, Lemmy has plenty and I’ve only ever used it on the Jerboa android app, never in browser. Stick with it, maybe some improvements will be made.
Sound like a big upgrade, congrats on your recovery!