You can try Mobius Strip.
I don’t know if he’s quite bitchy, but definitely not a softie and a former bully to the top:
https://www.mangago.me/read-manga/mobius_strip/
Other possibilities (not bullies, but not softies), maybe?
https://www.mangago.me/read-manga/kannousei_play_things/
https://www.mangago.me/read-manga/namae_mo_shiranai_machiawas......
