Short story:
Problem solved. Per Apple support's advice, did a manual transfer with an old external spinner. Instead of transferring the iTunes folder, transferred the Music folder. Then did a manual transfer from the spinner of the iTunes Library.xml file, which fixed it. The fix took five minutes with this last guy to make it all right.
Long story:
The chat and phone sessions would have been a joke if they hadn't eaten up three hours, due to disconnects, which meant starting over with each new advisor. After one of the junior advisors insisted on the need to upgrade to Ventura, I strongly requested someone else and was connected to a senior advsisor. After an hour, we disconnected to let the HD spinner do its hour to transfer the iTunes. Next day, had to spend 30 minutes with a junior before getting escalated to a senior. After an hour with her, the connection was lost. Back to chat as the only available option, I strongly requested a call with a senior advisor, which I got but was immediately disconnected. Called back and got routed to iPhone sales. Was routed back to support with someone who thought I was trying to sort out an iPhone problem. That guy got me back to the guy who had the right stuff.