Any one of these?
https://www.mangago.zone/read-manga/seishun_x_kikanjuu/
https://www.mangago.zone/read-manga/love_sick/
https://www.mangago.zone/read-manga/uwasa_no_midori_kun/
https://www.mangago.zone/read-manga/ssg_meimon_danshikou_keppuuroku/
https://www.mangago.zone/read-manga/hana_kimi/
https://www.mangago.zone/read-manga/kenka_banchou_otome_koi_no_battle_royale/
https://www.mangago.zone/read-manga/classi9/
https://www.mangago.zone/read-manga/men_s_life/
https://www.mangago.zone/read-manga/power/
https://www.mangago.zone/read-manga/kenka_bancho_otome_koi_no_battle_royale/
If not feel free to look through my list dear I hope you find it soon and/or enjoy the rest of the stories https://www.mangago.zone/home/mangalist/1581724/
I recall that I read this before.
She is a girl who was in the boys school? Then all of the guys there didn't know that she was a girl, and one of them is the ML