TIP: Problem with Verizon 4G LTE Network Extender resolved.
This morning I was working on a non-computer project when it occurred to me that it might be a good time to apply the most recent eero OS 6.13.2-26 update because I was offline.
So, I kicked it off and went back to work. I received the notification that everything was completed and my network was back up. Fine. Then I noticed that I had no Verizon cellular signal (after the update) when I usually have 5 bars because of the 4G LTE Network Extender (I have no useful service where I live from Verizon or any other carrier without the NE).
After trying three power cycles of the NE with no success and observing that it failed at the same point every time, I called and endured a Verizon Wireless chat session. The bot that chats with you assured me he/she/it could fix it, but of course the was not true. Finally got a Live Chat person who couldn't figure it out either, asking me to properly configure it, move to a different window, ... all of which I declined because the NE has worked great for year as configured and where installed with 9 of 11 satellites, etc. Last idea was to do a Factory Reset of the 4G LTE Network Extender.
Turns out that did it. The NE was hung up at startup protocol step 6 trying to set up IPSec connection to Verizon servers. Since the onliest variable AFAIK was a new eero OS install, and after eliminating the fact that my Network Extender was no longer associated with my new Verizon account, something about eero OS 6.13.2-26 apparently broke the NE. Perhaps it had squirreled away some parameters, but after the Factory Reset, it relearned them and everything is working fine.