This has come up a lot recently in tags of AO3 fics from (mostly teenage) users who migrated from Wattpad and TikTok, but to make this clear:
AO3 DOES NOT HAVE AN ALGORITHM.
For that matter, neither does FanFiction.net. (I came over to AO3 from FF.Net, so it wasn't too much of a culture shock. If anything, AO3 has more things to filter for than FF.net.)
People find fanworks by filtering through tags in the fandom they're in or occasionally by sorting through kudos/comments. There IS NO algorithm that pushes the "hottest" or "most liked" or "most recent" fics to the first page of a particular fandom tag.
USE THE TAGS PROPERLY so that readers can find your stuff. DO NOT post a work and then delete it only to repost it again so that it stays "on top". Furthermore, DO NOT post updates to multi-chapter stories as individual works: that is against the ToS of both AO3 and FF.net.
Not to mention, constantly reposting a fic so that it's "at the top" is annoying as fuck to both users and the volunteer staff.