Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
This is similar to my experience. You'll find my original question and the "solutions" to the problem. It now appears that there is no sure way to fix what Microsoft has done, and all the responses from Microsoft on this thread are just "Here, try this" deflections. Microsoft will not offer refunds, and it won't reel back and fix whatever the underlying problem is so all of the purchasers can uninstall the failed version and installed the fixed version. As I am now convinced from my original post, I paid $250 for vaporware. So did all of you, here.