I didn't watch Dear X but I read that it's about a female that was abused in her childhood, became sociopath celebrity, meet some male sociopaths that all took a liking on her, took revenge for even small grievances, and where a little less horrible person hurted a bit more horrible person and (ending spoiler ahead) that it has bad ending. So, maybe (partly similar, partly suited your requirement):
A Suffocatingly Lonely Death
Eyes of Heaven
Mouse
The Childe (movie)
Thicha