Update Changed Office 2016 to 365 and Requires re-authentication

An update processed automatically on July 24, 2020 that changed the look and functionality of Outlook and requires re-authentication of Word, Excel, and PPT. Also re-labels them all as Office 365 instead of Office 2016. This re-labeling has occurred once before but I found support to reverse it. Now I have changes made to the underlying apps. Can this be undone?
Windows 10, Version 2004, O/S Build 19041.388

I had something similar happening a week or so ago when the outlook open and close problem occurred. I tried to do a refresh via the internet and my office 2016 was changed to office 2019 which needed activation and refused to activate (*) when I tried it. I had to install a backup image which I made a month before and I disabled my office 2016 updates.

* The message was actually we cannot activate office 2019 because you are running windows 8.1

I also have office 2019 with windows 10 on a dual-boot - that is fine after a recent update (last week).