external monitor low framerate in games, overall choppiness

On ASUS ROG ally X, im using a dock with 9060xt and external monitor plugged in. While gaming on the handhelds display, everything works fine and performance is right where it should be but when playing on external monitor, the frames go significantly down and GPU usage never gets under 100%. I checked all the hardware and cables, even used another monitor just to make sure and nothing works