The Redmi Note 13 Pro automatically turns dark when playing games

If you use your phone for a long time at high intensity, the screen brightness will automatically decrease after the phone's body temperature rises to a certain level. Additionally, turning off the Auto brightness function will not brighten the screen.
This is one of the security strategies of the MIUI system, which can effectively control the temperature of the phone to avoid overheating and extend the life of the screen and battery. It is not a malfunction of the phone, so please feel free to use it.