Two Apple Tech support calls latter. Great help that both resolved as a hardware issue.
it’s definitely not a hardware issue as in a hardware failure. It is a hardware issue as in incompatibility with macOS Ventura. For some reason it cannot see the modem is connected to a router via WiFi.
I plan to test my theory with a Ethernet connection to see if that is the case.
The macOS is seeing my iCloud Drive as being almost full too. It’s 2 TB and it has 1.2 TB available according to the iCloud website when I login and check it. My iOS 16 iPhone function normally with iCloud.
MacBookPro 2017 1TB