Diagnosis
This is a common result of enabling HDR on a monitor with limited HDR peak brightness. The EX2710Q is VESA DisplayHDR 400 certified, which is a baseline entry-level HDR. Incorrect settings compound the problem.
How to Fix It
First, ensure HDR content is actually playing. In Windows, enable HDR in System > Display > Use HDR. Then, press the monitor joystick. Navigate OSD > Picture > HDRi. Do not use 'HDR' mode. Select 'Game HDRi' or 'Cinema HDRi'. These modes apply dynamic tone mapping more suited to the panel's capabilities.
If That Didn't Work
The underlying SDR picture settings are interfering. Before enabling HDR in Windows, go to OSD > Picture. Set Color Temperature to 'Normal'. Set Gamma to 'Gamma 2'. Set Black eQualizer to 10. Set Color Vibrance to 10. Now enable Windows HDR and select 'Game HDRi'. The image should have more pop.
Heads Up
In HDR mode, many standard picture settings are locked. Do not expect the same saturation and contrast as in SDR mode. The HDR effect is subtle on this monitor and is best perceived in a dark room with actual HDR10 content, not SDR content with Windows HDR enabled.