Click the “Change plan settings” link next to whichever plan you are currently using and then click “ Change advanced power settings“.Go into “Control Panel” and then “Power Options” Or Right-click on the Power icon on the taskbar and select Power Options.Restart windows and check This will fix “can’t adjust brightness ” bug.
You Can check And install latest updates from Settings ( Windows + I ) -> Update & Security -> windows update -> And check for updates. If the problem started after install windows 10 version 21H1, then make sure you have installed the latest Cumulative Update, As Microsoft mention: “ Addresses an issue with the brightness controls on some laptops after updating to the Windows Update.
