Found another glitch, this time with packaging. For some reason, the system-config-printer package puts the cupshelpers module in a separate directory, causing the Printers app in Cinnamon to fail. I checked a snapshot and the cupshelpers directory for Python 3.11 was installed in /usr/lib/python3.11/site-packages.
To fix this, make a symlink to the new module directory:
sudo ln -sf /usr/lib/python3.12/site-packages/cupshelpers-1.0-py3.12.egg/cupshelpers /usr/lib/python3.12/site-packages/cupshelpers