(If i’m not wrong, green-ish user here) When you click on “Communities” that’d be only the communities inside the instance that you made your account in.

I generally use this to look for specific communities: https://browse.feddit.de/ It should look across all lemmy instances to find the one you wanted

I would just check the communities on the top few instances

That approach is even more limited - it’s only communities hosted on lemmy.one.

This is the site you want to use to search across (most of) the fediverse:

https://lemmyverse.net/communities

The best I could do for your (very obscure) request is [email protected]

When you’re searching communities, it only shows you communities that are hosted on your home instance or that someone on your instance has either searched for before or subscribed to. So, if you know the exact link you’ll want to search for that, then once you do it takes a few minutes to federate if nobody has searched for it before. Give it a few, search again and it will now be in the results so you can subscribe. Otherwise, it might be helpful to have an account on a few high traffic instances so you can search from there to get better results and get the link to take back to the instance you want to actually use it on. I haven’t tried using a search engine to find communities but that might be another way to find them.