what are some bls where the mc has a revenge plan and dates the ml, but then actually fal...

Möbius strip

https://www.mangago.me/read-manga/mobius_strip/

But in the end it’s less that he regrets and more like he realized guy he was trying to get revenge on is the only one for him.

https://www.mangago.me/read-manga/zetsubou_ni_nake/

https://www.mangago.me/read-manga/renai_rubi_no_tadashii_furikata/
https://www.mangago.me/read-manga/tsukiatte_agete_mo_ii_n_dakara_ne/
https://www.mangago.me/read-manga/sakurada_senpai_kaizou_keikaku/

https://www.mangago.me/read-manga/fake_romance/

Netkama Punch?