DIAGNOSIS It's not broken; this is a classic Windows HDR configuration issue. The monitor is receiving an HDR signal, but Windows and your app/game aren't calibrated for it.
FIX You need to configure both Windows and the monitor's settings together.
- On the monitor, press the joystick. Go to Picture > HDR and select a mode. For general Windows use, try HDR Game or HDR Cinema.
- In Windows, open Settings > System > Display. Turn Use HDR on. Click on Windows HD Color settings and run the HDR calibration app (search for it in the Start menu).
- For SDR content (like your desktop), adjust the SDR content brightness slider in the same Windows HDR settings.
IF THAT DIDN'T WORK The content itself must be HDR. A washed-out look in a game usually means you need to find and enable the HDR setting within the game's own video/display options menu.
HEADS UP HDR on this monitor is best for consuming HDR movies/games, not for desktop work. The brightness and backlight behavior in HDR mode will make standard desktop apps look off. Toggle HDR in Windows off when you're done.