https://www.mangago.zone/read-manga/imitation_mate/
https://www.mangago.zone/read-manga/raising_beta_winnow/
I don't know what your tolerance level is, but I will warn you these guys are pyscho.
"Why Are You So Kind To Everyone Except Me?" https://www.mangago.zone/read-manga/why_are_you_so_kind_to_everyone_except_me/ I think this is in the softer side the ml is not batshit crazy but he is so possessive and calculative that is borderline creepy! Mc is so sweet and blind that he does not notice AT ALL
There's https://www.mangago.zone/read-manga/honey_trouble/ and https://www.mangago.zone/read-manga/secret_love_affair/ they are about a step crazier, in the novel of secret love affair the ml was worse but looks like that in the manhwa they decided to tone it down!!
Can you guys recommend me any bl or gl manga/manhwa/manhua that has a really possessive lover and their partner is just oblivious to that fact?