These are kind of everywhere regarding genre/plot but I think they're pretty strong!
https://www.mangago.zone/read-manga/unstoppable_hayeong/
https://www.mangago.zone/read-manga/ookami_no_musume/
https://www.mangago.zone/read-manga/yes_my_boss/
https://www.mangago.zone/read-manga/i_want_to_hold_aono_kun_so_badly_i_could_die/
https://www.mangago.zone/read-manga/skip_to_loafer/
https://www.mangago.zone/read-manga/pure_villain/
https://www.mangago.zone/read-manga/the_sensual_m/
https://www.mangago.zone/read-manga/liar_satsuki_can_see_death/
https://www.mangago.zone/read-manga/kanako_s_life_as_an_assassin/
https://www.mangago.zone/read-manga/super_baby/
https://www.mangago.zone/read-manga/umibe_no_q/
https://www.mangago.zone/read-manga/chouka_kou/
Not physically strong, but she's a cunning strategist (both in politics and military). She's a princess seeking vengeance against her uncle who murdered her family for the throne.
actual strong fml recs that aren’t as popular about revenge pls either mentally or physically strong