When you’re trying to find a community, in the search type in the whole URL. So for your example you should be able to make the instance find the community by typing in https://hobbit.world/c/hobbit_art in search all.
They’ll probably get mad that people can take their ball and go home by going to another instance without ads and signing away access to all of their personal data but get the same content. If they defederate, to me that’s the trash taking itself out.
Memmy’s on the App Store now. It does still have a TestFlight if there are any spots available but the app store’s version is currently up to date.