There's a "community" tab for your search results.
Liftoff!
A mobile client for Lemmy running on iOS and Android
Personally, I use an external site to search all instances. The search on an instance, and the app, only search for communities within that specific/specified instance. I don't wanna have to muck about adding instances to Liftoff that I've no interest in making an account for, and then making the same search several times on different instances to find what I'm after, so I do hope they add a function to search the entire federation as well as the individual sites.
There's a bug right now that search doesn't work if you haven't selected an instance you're logged into. I don't have a lemmy.world account, so the default selection would never search.
Once I selected my home instance to do the search tho, you'll see whatever communities come back under the relevant tab.
I have accounts on each of the instances that I browse.
The problem with search is that it seems to just return posts and communities from everything federated with the instance you are searching on.
So if I search for a specific community name I'm going to get tons of posts from tons of other communities mixed in, and I can't for the life of me find the community I'm trying to go to.
Which instance is your account based on? In my experience, using my lemmy.world account at peak server load makes Voyager very slow, Jerboa SUPER slow and Liftoff unable to load anything until I change to my .wtf account..
My main question is how do you go directly to a community. That's the primary problem, I can find a community, but if I want to go directly to it I can't find a way to do this.
Search isn't helpful because it seems to return results for all instances federated with the one you are searching. So finding something specific is a crap shoot of scrolling forever :/
If you're using Jerboa or Voyager, there should be links to the ones you're subscribed to in the menus where you decide the sorting of your feed, like this: