Big boy yaois

https://www.mangago.me/read-manga/yuuutsu_na_asa/

Shut line , walk on water

I'm glad you asked (beware though these are extremely toxic)
- do you still like me?
-Behind the scenes (side couple)
-Dear Benjamin (discontinued)
-checkmate
-Fate makes no mistake (side couple)
-Exotic love
-Shut line
-Payback
-Thirst
-Passion
-Lost in the clouds
-AoAo waiting to be eaten
-What’s the Probability of A Successful Love?
-Wet sand

Love in orbit
https://www.mangago.me/read-manga/love_in_orbit/

These I haven’t read in their entirety, but the bit I’ve read it seems like characters are adults about stuff.

Beware of the full moon in March
https://www.mangago.me/read-manga/beware_of_the_full_moon_in_march/

Under the green light
https://www.mangago.me/read-manga/under_the_green_light/

https://www.mangago.me/read-manga/hit_on_by_a_kinky_guy/ not whiney but still has his man pride(?) and not twink syndrome

https://www.mangago.me/read-manga/dreadful_night/
he doesnt suffer from twink syndrome only a bit in the further chapters

https://www.mangago.me/read-manga/the_foul/ he's actually almost smart and from what i read so far hes actually acts like an adult(?)

hope this is a good recommendation (￣∇￣")