Yo! I recommend The Missing O. The author is fantastic and it’s.. about adults lol
https://www.mangago.zone/read-manga/nerd_project/
https://www.mangago.zone/read-manga/murderer_llewellyn_s_enchanting_dinner_invitation/
https://www.mangago.zone/read-manga/kimi_no_yoru_ni_fureru/
https://www.mangago.zone/read-manga/monster_in_the_mist/
https://www.mangago.zone/read-manga/exotic_love/
https://www.mangago.zone/read-manga/geu_kkeute_issneun_geos/
https://www.mangago.zone/read-manga/fate_makes_no_mistakes/
https://www.mangago.zone/read-manga/smyrna_capri/
(I'd try reading more seinen, psychological, mystery, drama, etc. type stuff. Here's some that I like.)
Mushishi
20th Century Boys
Kiichi!!
Bastard (hwang Youngchan)
Oyasumi Punpun
Gangsta.
Kings' Viking
To You, The Immortal
Vinland Saga
Monster
Sunny (MATSUMOTO Taiyou)
Zankyou
Totsukuni no Shoujo
Berserk
Clover (tetsuhiro Hirakawa)
The Boxer
Phantom Tales of the Night
Recommend me something that u, as a fellow adult, find entertaining. Idk everything seems so childish to me these days, or maybe im just tired of the same tropes used over and over.