I know you’re specifically asking about Mastodon but consider checking it firefish as well. It’s got a lot of quality of life features that Mastodon still does not. That said the app situation is a lot rougher. Most Mastodon apps do work with firefish but every now and again something seems to break. If you’re looking for an instance firefish.lgbt is pretty solid but a little on the small side. Of course everything federates so that should be a huge issue unless you’re really into local.