Idk if its what you're looking for, but -"BL Game Rebirth: My New Life as the Hero’s Younger Brother"
and Hina Change- boy and a girl change bodies (but without reincarnation) reply
3 options for you
https://www.mangago.me/read-manga/ng_life/
This one has a rather important side character that was female in past life but male in current life. (fluffiest)
https://www.mangago.me/read-manga/bokura_no_kiseki/
This one has a main protagonist who is male in this lifetime but their past life (female) heavily influences their cur...... reply
