Mine is in the middle of the progress bar on the Apple black screen since 90 minutes. I know it can be very long (last one took one hour) and I’ll try resist pushing the power button till a few more hours…Be careful updating to 12.6.9, it bricked my 2019 16" MBP. Was stuck on black screen apple logo update progress bar for like 3 hours, had to restore from TM backup.