The Beast must Die is a good one. Not the most fucked up one but interesting! I love the art cause it gives that awkward feeling and pairs up so well with the story
The most fucked up yaoi manga I've ever read is "No Reason", I don't recommend it if you have a sensitive stomach.
into the rose garden, a trace of margins, form of broken love, sheep’s mask
they all got plot and imo are worth a read ! not really the most fucked up ones i’ve read but still really good
Broken Boy
Just recommend me the most fucked up yaoi mangas out there.