Samsung Galaxy S21+ 5G
Android 11.0
1 Find "Display"
Slide two fingers downwards starting from the top of the screen.
Press the settings icon.
Press Display.
2 Adjust screen brightness
Press the indicator next to "Adaptive brightness" to turn automatic brightness on or off.
Drag the indicator right or left to set the brightness manually.
3 Return to the home screen
Press the Home key to return to the home screen.