So, I think I found a way.

Go to your subbed communities or filters (the list of subscribed stuff, next to the home button.

Tap on your instance. Change to ‘about’ It shows trending communities. At the bottom, there’s a ‘See all’ button.

There should be a simpler aay to get to it, but I’ve no idea how to design it, so I can’t offer suggestions

Beyond that, if you just want a list of local post feed, that’s available at the top of the home feed, you can select all, subscribed or local from instances you’ve added to lemmy.

Actually, this seems to be a common issue with all current lemmy apps. I haven’t found a single one that’ll do it.