I've always liked Hideshi Hino's Panorama of Hell from 1984. It's very edgelord, like the blood and guts variety. The art isn't great but it's unique and charming in its own way.

What I like about it is that it begins as this edgelord horror stuff about demons and hell, but as you progress further it becomes clear it's autobiographical about the author. About how his grandparents were yakuza. About how his parents were Japanese colonists in occupied northeast China during WW2. About how his mother learned she was pregnant right after Japan was atom bombed. It gets really into his psyche and how he feels about being conceived right at a moment of such horror and death.

It's very good and I recommend going into it with an open attitude to all the gross stuff

For something lighter I really like My Brother's Husband. Really charming story about how to cope with loss of a loved one, and how to accept people into your family despite differences. It's cute and a rare, but increasingly common realistic portrayal of queer people in manga.