Jul

unchanged mannnnnnnnnnnnnughhhhh

Not sure if it's similar but the name just kind of popped up : Checkmate

There is one aspect similar, them being 1st and 2nd in the class and the guy in the second being bitter about it while the guy who is 1st doesn't even notice it. Then one of them tries to take control of another's life later in the future.

this ruined me do u have more recs

if ur really into the psychological vibe go for harada's works.,,,,,, major trigger warning for them though they're all heavy topics

other than harada's works there's :
https://www.mangago.me/read-manga/bait/
https://www.mangago.me/read-manga/two_in_six_billion/
https://www.mangago.me/read-manga/warehouse/
https://www.mangago.me/read-manga/black_mirror/

sorry if theyre not what ur looking for this is all i could think of </3

Ah yeah I remember now there was that thing going on, thanks

There's another one that came to mind: My brother's lover. It's been so long since I've read it (not to mention that it was also the kind of story you have two reread to connect all the dots). I think just one or two things are similar or maybe I'm def wrong