oh I didn't mean it that way, no need to apologize. I just notice this question comes up a lot inside different communities, people often wonder why there are also two/three/N other communities and why don't they all merge. It highlights a lot of people still expect things to be centralized even in a decentralized space. But, it's good that you ask, so hopefully more people understand better why it's good thing to avoid monopolies on topics.

The search function should function the same way as the search function on the official web interface. That means however, unless you're searching the url of a specific community, it can only search for communities, comments and posts on instances it has cached. If it hasn't had a member visit a community at least once, it won't know it exists.

I recommend browse.feddit.de to search for communities, and for newly created communities, you can search through the posts in !newcommunities@lemmy.world

There are many other places to look, you can find multiple lists of communities that migrated from Reddit with a quick google search.