pls suggest tragic/depressing manhwas, any genre but preferably no romance

I will recommend you some but read it on your own risk.

Pigmen
killing Stalking
Sweet home
strangers from hell
Bastard

https://www.mangago.zone/read-manga/boku_no_gemini/

unfortunately i've already read all of them

Read some of them ....-Distant Sky -Ventham -Perfect Victim -Undead King -One Day, Suddenly, Seoul Is