Disclaimer: I don't really have any recommendations for the exact type of possessive ml you seem to be looking for, the ones I've seen myself that have that kind of "bad guy" lead tend to be older dramas with less satisfying romances/kiss scenes or simply boring plots like Easy Fortune Happy Life so I don't tend to recommend them. Here are the ones I think fill some of what you're asking for:
I second Todome no Kiss^^ (if you're going to watch it, there is an epilogue episode in the spin off todome no parallel you should be able to find somewhere, it finishes off the main story)
Less dark than Scarlet Heart if you're in the mood for this trope but the fluff version, in The Romance of Tiger and Rose the ml is sent to the fl's kingdom for marriage but has his own secret mission and he tries multiple times to kill the fl lead in the beginning, but he ends up falling for her and becomes totally whipped for her. Powerful and protective.
You've probably seen it, but any version of Boys Over Flowers has this. The school bully that ends up falling for the girl and being really possessive of her. I personally think the OG Taiwanese version is the best because I love the ridiculous hair, but in all seriousness; Thailand is coming out with a version later this year and the trailer looks really good.
This one has a minimal, slow burn romance, they've been hinting at it for the whole drama but it's still airing so idk if they'll end up together... Vincenzo. the ml is in the mafia, totally antihero, doesn't hesitate to beat up/kill anybody he needs to which includes getting revenge for the death of the fl's dad. It's so satisfying to watch him kick ass after seeing so many dramas where the leads are insistent on "we have to win the right way."
This one depends on how you view vigilantes, but City Hunter (the korean drama version) is definitely seen as an antihero within the story. He's acting as a vigilante in order to get revenge for his uncle, who isn't the best guy either so the whole story is pretty dark. He also gets pretty jealous and protective over the fl. Lee Min Ho's best drama, imo
more dramas about revenge:
Innocent Man might also fit what you're looking for? It's been a hot minute since I saw the drama but the ml starts out good but gets screwed over within the first episode of the drama then the rest is about him trying to get revenge on the fl's family (she also hates her family and their involvement together early on is where my memory gets fuzzy). I wouldn't really describe him as a possessive ml tho, just morally grey.
Behind Your Smile has a girl from a rich family brought to ruins by the male lead who is out for revenge. He gets close to her for revenge and ends up falling for her. It doesn't exactly fit what you're asking for since she doesn't know he's a bad guy in the beginning, but the audience knows there's an ulterior motive and watching him battle between his wish for revenge and not wanting to hurt her was pretty entertaining.
Secret (2013) and Kleun Cheewit (2017) are both very similar dramas with a female lead that gets into a car accident and ends up killing the male lead's fiance (altho in Secret, she wasn't actually the one driving) and the male leads in both stories become obsessed with getting revenge and that obsession eventually ends up turning into love. Not the misunderstood, everyone else sees him as a bad guy ml you were asking for because he's really only a bad guy to the girl, but both are possessive of the fl. (I personally preferred Secret, I thought the character development was better paced, but a lot of people really enjoyed Kleun Cheewit.)
Arthdal Chronicles could potentially fit your prompt exactly if it ever gets its second season, but covid kinda screwed that over... otherwise the story is unfinished and i wouldn't start it unless season two gets greenlit.
For movies, I'd check out Wolf Girl and Black Prince? Again it's been a while since I watched it, I think it fits what you're asking for, but less dark than scarlet heart since it's set in modern times and high school.
