DIAGNOSIS This is almost always a mismatch in color profile or range settings between your computer's graphics output and the monitor. Sometimes the monitor's 'MagicBright' or 'Eye Saver' modes are enabled by default, which drastically alter color and contrast.
FIX First, on the monitor itself, press the joystick to open the menu. Go to 'Picture' and set 'MagicBright' to 'Custom'. Then, go into 'Picture' settings again and make sure 'Eye Saver Mode' and 'Eco Mode' are set to 'Off'. This gives you a neutral starting point. Next, on your Windows PC, right-click the desktop, select 'Display settings', then 'Advanced display'. Look for 'Color profile' and try setting it to 'sRGB' if available.
IF THAT DIDN'T WORK Your graphics card might be outputting a 'Limited' color range (16-235) while the monitor expects 'Full' (0-255). In your AMD or Nvidia graphics control panel, look for a setting called 'Pixel Format', 'Dynamic Range', or 'HDMI Color Depth' and switch it to 'Full RGB' or 'YCbCr444'.
HEADS UP The 'Game Mode' setting on this monitor can oversaturate colors. If you have it on, try turning it off for general desktop use and see if the image looks more natural.