Eh, IRC and Usenet were both federated systems that had a ton of technical issues when they kicked off that got fixed over time via protocol and code changes. I would guess that discoverability is probably one of the things that'll be improved -- right now, using the Lemmy Explorer is kind of an important tool for people using small instances.

https://lemmyverse.net/communities

I don't think that that's the end-all-be-all of discoverability, but it works well enough for me now.