Yeah Mokyeon's body changing is literally a plot point... He mentioned before how it's hard for him to keep his weight on and that he has to train a lot to keep his muscles, and there's literally a transition between how he was before and how he is now after Nanjo "dumps" him in chapter 35, with his hair getting longer and his body becoming thinner. It's fine to like the former artstyle, but I prefer it now because as you said they look more proportionate and less with exaggerated yaoi body proportions.

guys guys guysss urrmmmm SEE NO OFFENSE TO NOBODY OKAY but like DONT Y'LL THINK BOTH OF THEM HAVE BEEN TWINKIFIED see i get it, things were rough an all BUT LIKEEE BBOBBBBBB its somehow not settling w me. i think something is wrong w the art or did something really happen and i am not aware abt it??