The only thing I remember is one of the main couples trying to ask a gay classmate for advice and that gay classmate thinking he was gonna blackmail him(they're not a couple just friends)
https://www.mangago.me/read-manga/someone_else_s_bl_manhwa/
is this what you're looking for?
It had REALLY casual trans rep with one of the supporting characters in the bathtub telling the mc that if they didn't find the character being trans weird,why was he so against him being homosexual and the main character was like yeah you're right god damn
https://www.mangago.me/read-manga/haru_ga_kita_kome_tasu/ this maybe? the only thing I remember about is the bathtub part lol
YES IT IS THANK YOU