Games are using RGB, while movies/series are for YCbCr output. So most TV's do only support YCbCr, while monitors are made for RGB. YCbCr has a limited color space compared to RGB, so using a monitor for gaming is the best option. If you're using a monitor on a console, make sure you choose the RGB or full color output in the settings.
Frankly I've only used monitors for anything for a decade now to avoid all the horrendous pointless "smart" LOVE they keep shoehorning into TVs.
Amen to that mate LOL 1st thing i do with a new TV is turn off everything smart related and plug the calibration disc in the player