In the past, we've made a thread in Beehaw support to ask people what they wanted, did some filtering of our own and then included it in our Community Survey.
I don't think we'll do one very soon considering not all of the communities are up yet.
So far it seems that the admins will make posts when they’re considering new ones. I think the need for committed moderators may be the challenge for adding new ones. You could always find a community on a different Lemmy instance or create a community on an instance that has that enabled.