Monterey 12.7.4 won't update

I am running Monterey 12.7.4 (21H1123) on an iMac Retina 5K 27-inch, Late 2015 model. Appartently there is a Software Update available for the system, but when I try to run it from System Preferences, or About This Mac / Software Update, System Preferences always quits unexpectedly. I have tried Safe Mode, deleting preferences and reinstalling Monterey – but so far, no fix.

Any ideas?

Monterey 12.7.4 won't update
 
 
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