Thanks for your reply(s)!
I've had problems with this computer since the day I bought it. Most of them showed up after the warrantee period.
The biggest problems came after trying to upgrade to MacOS Monterey. The computer froze during installation and nothing I did would make it boot up in any configuration.
After 2 trips back to the Apple Authorized Service Center, they managed to get Monterey installed, however the computer has never worked correctly since.
I haven't beat myself up over it because I have order me a new Mac Studio computer (August delivery!). I just need to limp along on this iMac Pro until the new machine arrives!
Thanks again!