some of these details might be fuzzy or wrong, but it is one of those historical shoujo isekai manhwas. there is a school/academy where there are fan clubs for two of the male leads, the ogfl was obsessed with one of them and lead a fan club, and the male lead disliked her, but after the isekai, she became normal. and circumstances led her to join the student council and have to interact with the male lead(s).
i don't know if im making this up, but is there an isekai type webtoon/manga where the male lead recognizes reincarnated female lead from a past life or something, and spends a significant amount of the story begging her to admit the truth that she is the person he's looking for/has lost? pretty sure its straight but could be a BL, not "love thy enemy" but similar vibe with ML being able to recognize FL through her mannerisms and personality.
dont think this is the manhwa ur looking for but this fits (gets reincarnated into diff body, same timeline)
https://www.mangago.me/read-manga/now_come_and_regret/
just casually binged one of the best manhwas ive ever read