hmm try these:
https://www.mangago.me/read-manga/trash_of_the_count_s_family/
^ most similar to what you want
https://www.mangago.me/read-manga/the_scholars_reincarnation/
https://www.mangago.me/read-manga/omniscient_reader_s_viewpoint/
https://www.mangago.me/read-manga/the_descent_of_the_demonic_master/
https://www.mangago.me/read-manga/kill_the_hero/
https://www.mangago.me/read-manga/herscherik_the_epic_of_the_reincarnated_prince/
I've seen the trend of women reincarnating into daughter of dukes or kings/emperors, or even the girlfriends of the male lead or 2nd male lead and the villainess too.
But is there anything about males reincarnating into male leads? Knights, princes, or anything?