codename anastasia? super basic tho T-T (action kinda starts in the novel tho)
https://www.mangago.me/read-manga/unfinished_relationship/
A tree without roots
This one is biggest example -
https://www.mangago.me/read-manga/formless/
https://www.mangago.me/read-manga/passion_1/
I think this one is a good match and I do think the seme would try to kill the uke but doesn't and it's because he actually likes the protagonist so I'm not sure if it is what you're looking for.
Ah nevermind you already mentioned it haha.
genuinely need bl with seme that is literally dangerous and would kill people, even the uke. For ex, passion, roses and champagne