By default games are sorted by popularity, which works in an obfuscated way so people don't try to play tricks. New games are given a boost at first; later it also depends on how many people see or download or rate your game, things like that. Yours is very new, so it's going to dip lower in search results until people have interacted with it for a while. Might want to also advertise it outside of Itch until it gets more popular.