Stalker

Vassalord

(Not sure how old you want them to look, but here's some where the main character(s) don't have a baby face)
Gangsta.
Clover (tetsuhiro Hirakawa) (mc's are in highschool but could pass as 20-30 year olds)
20th Century Boys
Monster
Ojisama to Neko
Saint Oniisan
Kings' Viking (mc is young, but I wouldn't say he has that much of a baby face normally. Other characters are older and look older)
Unhinged
Hanamonogatari

Forgot to say but Warning: some of these contain dark themes/images

shutline, marcel (has rape scenes in the latest chapters so watch out), master x secretery, Trap Caught by Chance (this is straight up porn but uh it has old guy as bottom)

i double checked to make sure that all the mcs have wrinkly faces lol
SUI mo AMAI mo - gay 60 year old couple
Hanamonogatari - old woman yuri
Yuminari - middle aged x old man yaoi
Jijii No Koi - 80 year old man yaoi...
A Wolf and A Bear - older man x adult man
Midnight Rain (CTK) - adult manly men yaoi
Don't Call Me Daddy - unrequited? love old man yaoi
Yuki to Matsu - no wrinkles but these are two very adult men and the art is seriously beautiful

as for not romance,
The Fable - drama, seinen
Vinland Saga - seinen, historical
Golden Kamuy - seinen, historical, adventure
Kaiji - Seinen, gambling, drama
Dorohedoro - fantasy, horror, seinen
Hajime no Ippo - Sports, drama (yes the mc is young but the artstyle kinda makes up for it and makes him look old lol)

Thanks to all of you guys! I'll be checking all of these ( ◜‿◝ )♡

In the doghouse
You can give it a try

That's the exact one i read that made me want more lol

So difficult to find consensual femdom bdsm