How is the first person supposed to find a specific community without discovery

I think discoverability is one of the biggest issues facing the fediverse in general and the threadiverse specifically. There are third-party sites that try to catalog the wider ecosystem of communities (like lemmyverse - click the dropdown to switch between lemmy/piefed/mbin), but relying on third-party services like that is far from an ideal solution, and it is a barrier of entry to casual, non-techie users.