search only finds users who start with the search term
When you search for a user, it only finds results that start with your search term; it would be much more useful (at least to me) if it found results that contain the term.
The specific example that inspired me to open an issue was searching for an account I'd just added to the instance I use to mirror Twitter accounts so they can be followed from the fediverse (https://twitter.oksocial.net); the account is "PlayARKMobile", but all I could remember was that it was related to Ark.
Searching for "ark" on that instance finds no users, but searching for "play" does find it.
(I had to look back at the the mirror config for the username. :-)