Hello , netlocksep
Thank you for contacting our Microsoft Community !
You can try the following options:
Open the Action Centre by clicking on the notification icon on the right side of the taskbar (you can also use the shortcut Win + A).
In the Action Centre, find and click on the Screen Brightness Adjuster (an icon in the shape of a sun), which will open the Display Settings.
In the display settings, find the "Brightness and colours" section, where you should be able to find the Adaptive brightness option. Try turning it off.
You can also try opening "Control Panel" -> "Power Options", find "Change advanced power settings" under the currently used scenario, expand the "Display" option, find "Automatically adjust screen brightness" and set it to "Off".
If you don't understand or have any questions,
please feel free to contact us!
Best Regards
Bobhe | Microsoft Community Support Specialist