Yessss! Honestly that's like 50% of BL LOL. Not all of the ones I'm listing are at the same level of angst regarding how badly the ML treats the MC. Some are much more brutal, others fit the description a bit more loosely. These are just the ones I believe have a similar trope to what you're requesting that I've read or have angst.
Painter of the Night (completed but not all chapters are uploaded on here)
BJ Alex (completed)
Code Name Anastasia (on going, the love part hasn't kicked in yet so may want to let it marinate)
Jinx ( on going and again the ML love part hasn't been shown yet either)
Dark Fall (ongoing)
Down and Dirty (completed)
Legs that won't Walk (completed on side stories now)
Low Tide in Twilight (ongoing)
Passion (ongoing)
Profundis (ongoing)
Roses and Champagne (completed, side story ongoing I think??)
Yours to Claim (completed)
Limited Run (completed)
Crossing the Line (ongoing)
Paper Flower (completed)
The Third Ending (completed)
Thank you! ╮(￣▽￣)╭
you're welcome
If you have other reccs I'd kindly take them ╥﹏╥
some of my other recommendations that I enjoyed reading are:
Dawn of the Dragon (ongoing)
Don't be Nice to me (completed)
On or Off (completed)
Love or Hate(Yeongha) (completed)
Dangerous Convenience Store (completed)
Caste Heaven (Yaoi) (completed ??)
Seeing Double (completed)
These don't follow the "a-hole ML with regret and angst" trope but I think they were good reads (▰˘◡˘▰)
Can someone reccomend me story like this with this trope where ml treats mc badly and doesnt care but then he regrets and falls in love with mc?