I was not was not aware the the older tag syntax for Google Assistant had been deprecated in early 2021.
https://community.openhab.org/t/openhab-app-in-google-home-uninstalled/127869/4
Now 12-18 months later, support for the old syntax has been discontinued. I am still able to run openHAB2 but just need to update my items definitions to use the new tag syntax.