Yep i figured that out as well. but it's difficult since when you click reset game sets to 4k res, then my cursor doesn't highlight what it's on, so i have to blindly move my mouse around until i see the res highlight then move again until i see 2k res highlight (for my monitor), then move around until i get apply button to highlight, then finally i can operate rest of settings normally again.
Maybe has to do with me trying to play in fullscreen, i may just try window mode if this problem persists.