The automatic brightness feature reduces eye strain and extends battery life, while a sensor scans the surroundings and always selects the best brightness.

Note: The automatic brightness can also be turned on or off using the quick settings.

Android 10 | ColorOS 7.0
Step 1:  Open the  Settings
Step 2:  Tap on  Display & brightness
Step 3:  Enable or Disable  Auto brightness
  1. Open the Settings
  2. Tap on Display & brightness
  3. Enable or Disable Auto brightness

Oppo Instructions