https://www.mangago.zone/read-manga/beware_of_the_full_moon_in_march/ (emphasis on the REALLY BAD treatment.) but it has exactly what you’re looking for & it’s very satisfying.
https://www.mangago.zone/read-manga/legs_which_cannot_walk/ ; things get worse later on in the story, seme becomes crazier & much crueler. uke gets hurt shortly after & it’s almost fatal.
https://www.mangago.zone/read-manga/palace_of_bardo/ ; a past life manhwa, seme is cruel in their past life & results in uke getting hurt.
https://www.mangago.zone/read-manga/sadistic_beauty_bl_sidestory/ ; not at all for the faint of heart. treats uke horribly, uke is severely injured at the hands of multiple people & seme changes. uke also hurts himself but it ends well (kind of.) severe content warning.
Just finished reading flip the script and I want a bl where seme was treating uke really badly but then the uke got seriously injured so now the seme's losing his mind