Safari Notifications Scam
Not sure where it came from, but I started getting notifications that looked like Apple System Update notifications. These were actually Safari notifications made to look like System Updates. I searched for solutions, but mostly just found recommendations to block websites, disable extensions, or use Screen Time controls.
The solution was easy - go to Safari->Preferences->Notifications and remove the offending notifications from the list.
Chuck
MacBook Air 13″, macOS 12.6