Ok so it is indeed a 1440p monitor (2560x1440p native).
Are you sure that the options in-game aren’t just misreporting, and in reality it is actually set to the correct one? Happened to me iirc.
When you launch the game with the option that you have, does it look weird, blurry or more grainy?
P.s. by misreporting i mean exactly what happened to @Xan84 (shows 4865x2036 but in reality it’s 1440p)

