I'm looking for f*cked up mangas like Dead Tube or Trash.

i got you dawg

listed vaguely from least to most fucked up.

series
Osamu Tezuka - The Book of Human Insects
Osamu Tezuka - Ayako
Kazuo Umezu - Senrei
Tetsuya Tsutsui - Manhole
Naoki Yamamoto - Arigatou
Akane Torikai - Sensei's Pious Lie
Yousuke Nagase - Umareru Kachi no Nakatta Jibun ga Anna no Tame ni Dekiru Ikutsuka no Koto
Tomiyaki Kagisora - Happy Sugar Life
Inio Asano - Goodnight Punpun
Kyoko Okazaki - Helter Skelter
Saizou Horihone - Drainage City
Koutarou Ookoshi - The Love That Binds Us to Heaven
Suehiro Maruo - Shoujo Tsubaki
Waita Uziga - High School Girl in Concrete
Suehiro Maruo - The Caterpillar
Jun Hayami - Hentai Shounen
Melibe (Fuyunaga) - Burgess no Otome-tachi

one-shot collections
Yoshiharu Tsuge - Nejishiki
Yoshihiro Tatsumi - Push Man
Yoshihiro Tatsumi - Good-Bye
Suehiro Maruo - Paranoia Star
Shintaro Kago - Kijin Gahou
V/A - Hell Season
Jun Hayami - Beautiful Imprint

individual one-shots
Naoki Yamamoto - The Voices That Call Me
Jun Hayami - A Good Day to Die
Jun Hayami - An Ugly Daughter Like Me
Shintaro Kago - An Inquiry Concerning A Mechanistic Worldview of the Pituitary Gland

these are just stuff that i can personally recommend because i've 1) read them and 2) i thought they were interesting literary works in one way or another. there are plenty more that i'm familiar with but that don't meet those conditions and that i simply can't recommend. lol.

I have yet to read a manga authored by either of these two and not feel deeply uncomfortable:

SAMURA Hiroaki

MATSUMOTO Jiro

If you want something more trashy:

Tomogui Kyoushitsu (The Friends-Eater Classroom)
Jinrou Game (And its sequels)

I didn’t read the manga you’re talking about, but I think these series are twisted in the way you’d like.
Series:
-Ayako by Osamu Tezuka
-Sakuragari by Yuu Watase
-Happy sugar life by Tomiyaki Kagisora
-Kaze to ki no uta by Keiko Takemiya
-Zankoku na kami ga shihaisuru by Moto Hagio
-Elfen lied by Lynn Okamoto

Oneshot
-Hakoiri Musuko by Mitsuaki Asou
-Yasha gozen by Ryouko Yamagishi

I think you could like the comic “Nine stones” by Samuel Spano as its artstyle is inspired by manga one and the story is dark and twisted.

Finally remembered the name of the series that immediately came to mind when I saw this thread: Ogeha.

I also remember Pupa and Switch Witch by Mogi Sayaka being particularly strange and fucked up.

Very interesting threads. There are lots of great recommendations, I'll list something I can remember now:

Emergence