Thank you, that makes sense - I do feel like there should be the option to search unfederated communities without having to know the explicit name & instance, but maybe I’m wrong :-)
I’ve opened a feature request with wefwef dev, thanks for explaining how things work round here !
Basically I made a community on lemmy.fmhy.ml and then searched for it on a different instance and it wasn’t coming up, and apparently you have to search !community@instance and subscribe and only then will the community be searchable/accessible from the other instance.