DIAGNOSIS The default picture mode is likely set to Gamer 1 or a non-color-accurate preset. The monitor's wide color gamut (DCI-P3) can also look oversaturated if not managed correctly by the GPU.
FIX Press the joystick to open the OSD. Go to Picture. Set Picture Mode to sRGB. This locks the color gamut to the sRGB standard, which is used by most web content and games, and locks many color settings for accuracy. If you need adjustability, use the Custom picture mode. In Custom, set Gamma to Mode 2, set Color Temp to Custom, and adjust R, G, B gains to 50 each as a neutral start. Finally, in Windows, run Display Calibration and ensure the "SDR color appearance" slider is set to the middle (or preferred) position.
IF THAT DIDN'T WORK The signal from your GPU may be incorrect. In the NVIDIA Control Panel, under "Change resolution," ensure Output dynamic range is set to Full (not Limited). For AMD Radeon Settings, ensure Pixel Format is set to RGB 4:4:4 PC Standard (Full RGB). A Limited range signal will crush black and white levels, causing a washed-out look.
HEADS UP The monitor's HDR mode (labeled HDR Effect in the OSD) is simulation-only and not true HDR. For SDR content, keep HDR turned off in the Windows HD Color settings and the monitor's HDR Effect mode off to avoid distorted colors and brightness.