Dillocircus 
Moderator
cub appreciator
I think the search is server-limited, obviously. I’m no on it, but from what I gather it’s a lot more like tumblr than “traditional” social media. Even more so than Bluesky, which is 100% chronological on your personal feeds, but has a FYP with a significantly less advanced algorithm than Twitter. Like, what is it with those algorithm and showing you stuff you’ve already liked or even reblogged? How else do you expect to further engage with that post, Bluesky/Twitter?? (Tumblr’s algorithm meanwhile, will happily recommend for following users that you have blocked or have blocked you… or both)
Anyway, the search is bad because in practice on Twitter and twitter clones most people don’t tag (though I guess it may depends on individual server?). I rarely see hashtags on my twitter feed, and they are basically entirely absent from Bluesky. Also it should be noted that any server can refuse to interact with another, so there will be servers that you can’t reblog/retweet/retoot/whatever-the-fuck-the-word-is-on-Mastodon from.
What do you do? Find your “starter stable” of accounts you want to follow. I assume if you wanna join Mastodon, you’re already checking the feeds of a few people regularly. When I joined Bluesky, I had about thirty+ people already who had fled twitter largely or entirely. If you don’t have that, why do you want to be on Mastodon exactly?? Throw in tags of interest, so you don’t even need to search for them.
Now, remember, there will be no algorithm to spoonfeed you content (or spread your stuff if you post yourself), so now your job is to interact if you want to get noticed. Retweet, like, respond. That’s how people will notice you. Check the original poster of good posts. If the account looks good? just follow it instead of relying on other people to push it onto your feed.
Be your own algorithm. Refine your block/mute filters over time to prevent stuff you don’t want on your feed. It can be some work, but it’s good hygiene for the mind to learn to do this! (it makes you learn how frustrating it is that you can’t do it on Facebook, for starters!)
Basically that’s my advice, based on how it works on Tumblr, and given that (tagging culture aside) Mastodon function much similarly in practice.
(if your question is more about the technicalities of “where are the useful functions” and “how the fuck this interface works??”, then I’m afraid I can’t do anything for you 😅😅)
