SOLVED Unable to adjust brightness

[WordStar]

After update 21H1, lost ability to adjust screen brightness; F2/F3 do nothing; Slider gone from Display Settings; MS says slider will appear in Action Center - It does not!! This is an essential function. I updated Intel HD graphics 620 driver - no help. Computer: HP Pavilion X360 14-ba051cl

 

[WordStar]

SOLVED: It took an hour with HP's automated help before it suggested doing a HARD RESET. After that, the slider is in the Action Center, as promised by MS