Didn't mean to follow but I'll suggest
Blind Play
https://www.mangago.zone/read-manga/blind_play/
List with darker themes here that hopefully fits what you're looking for: https://www.mangago.zone/home/mangalist/906214/?filter=&page=1
Warehouse might be more in line with what you're looking for in terms of kidnapped/raped/stockholm syndrome-y vibes:
https://www.mangago.zone/read-manga/warehouse/
Also would recommend The Beast Must Die, that I personally felt had the psychological thriller component that Killing Stalking has:
https://www.mangago.zone/read-manga/the_beast_must_die/
So I’ve been wanting to experience the feeling that I did while reading “Killing Stalking”. If you have any scary, intense, or sad yaoi/bl webcomics than please tell!