here are my personal b&w favorites (disclaimer: if u were looking for pwp then this are not it):
stalker’s game
stigma
a painter behind the curtain
radio storm
The first two manhwas start our in black and white, but their side story episodes are in full color:
1. Heat and Run
2. Lover Boy (Zec)
I also really like mangaka Megu Iroha's works too.
Sangyang:The Wanderer
https://www.mangago.me/read-manga/sangyang_the_wanderer/
https://www.mangago.me/read-manga/o_g_oh_my_god/
It's a personal favorite with its art style
90 days for the delicacy
Black and white BLs with very tasty and good artstyle?