DIAGNOSIS: You're probably seeing the default factory settings, which can look flat, or the monitor might be stuck in a non-standard color mode like 'Cool' or 'Game'. This is a quick settings fix.
FIX: Use the joystick button on the back of the monitor to open the OSD menu. Go to Color > Preset Modes. Try Custom Color first—it's often the most accurate out of the box. If that's still off, go back to Color and make sure Color Space is set to Standard (not sRGB or AdobeRGB) for general use. You can then fine-tune Brightness and Contrast from there.
IF THAT DIDN'T WORK: Check your computer's graphics driver settings. Sometimes Nvidia Control Panel or AMD Adrenalin software applies its own color/contrast enhancements that conflict. Reset those settings to default. Also, ensure your GPU is outputting RGB Full Range (not Limited) in its control panel.
HEADS UP: The monitor's sRGB mode locks most color adjustments to enforce a color standard, which can look duller by design. It's great for color-accurate work but not ideal for general browsing or media consumption where you might want more vibrancy.