Screen won't dim after iOS 13.7.1 security update.

I was all sorts of happy with Ventura on my MacBook Pro, even thought I keep getting this annoying Sequoia upgrade notice. I did see a security update for Venture (13.7.1). So,against my better judgement I decided to do the security update. Now I cannot dim my screen. It is Full Bright. How can I fix this? Please, don't say upgrade to Sequoia - it will only slow my machine down and I'm not impressed with Apple's dribble ware.