ml dresses up as a girl and fl is a maid
https://www.mangago.zone/read-manga/company_and_private_life/
That's probaby not it
Is the ML white haired?
This? https://www.mangago.zone/read-manga/the_lady_i_served_became_a_young_master/
https://www.mangago.zone/read-manga/your_majesty_please_don_t_kill_me_again/ this?
ml dresses up as a girl and fl is a maid