problem fixed…saga of internet resets for past year

Over a year ago I started my t-mobile home internet journey with the 5G Nokia modem.  In that year I regularly followed this forum, and early on added a fan under the modem thinking heat was the issue.  I have Wi-Fi turned off and use an eero mesh network for Wi-Fi connected to the grey cylinder.  I have varied upload and download speeds, but overall very satisfied.  I regularly use YouTube TV and computers.
 

Starting 5/14/21 it seemed to randomly fail every few days.  I added the fan on 6/10/21 and magically until 12/8/21 I had no resets, SEVEN months.  The symptom and fix are always the same.  The internet goes down, eero Wi-Fi is still available, I check on Speedtest, and internet is down, then I push the power button on back of the grey cylinder off for 30 seconds, and then back on.  The internet always comes back on immediately.  The eero network detects it, and within a couple of minutes everything is fine.  After 12/8/21 I have had random internet down, and had to reset often, sometimes every day, sometimes up to a week or so between failures.  It appears that after 12/8/21 the magic of the fan no longer works.

through 6/7/22 I have documented 31 resets of the grey cylinder to get the internet back.   
 

on 6/8/22 I made a major change, I added a Keep Connect Wi-Fi switch to monitor for internet going down.  The grey cylinder plugs into the Keep Connect, and checks every minute to see if the internet is available on my "guest" eero network. If it is not it turns power off to the grey cylinder for 30 seconds then turns it back on.  It really works, I have not needed to manually reset the grey cylinder.

But, I learned some new information.  Those 31 resets were all during times I was using the internet, but the Keep Connect has detected multiple resets during the night.  
 

6/12/22 10:20 pm Keep Connect reset for first time, four days after I installed Keep Connect.  I was using internet at the time and had noticed it went down.  It came back automatically, success!  I always check my eero network and Speedtest to verify.

6/14/22 3:58 am, Keep Connect reset.  I would never had recorded this middle of the night reset. Would the system have recovered automatically by morning if Keep Connect hadn't done reset.

6/15/22 power went out at our home on 6/14/22 at 10:30 pm, and came back on at 12:30 am on the 15th.  The internet came back, and everything checked out.  BUT…four hours later at 4:05 am, 4:22 am, 4:34 am, 4:56 am, and 5:11 am I got notice that Keep Connect had detected internet failure, and did reset!  Five failures and recovery before I got up to everything working fine!  Keep Connect sends me text message whenever it does a reset.

6/16/22 9:10 pm, Keep Connect reset.  
6/23/22 1:29 am, Keep Connect reset…. I never would have noticed this one?

6/25/22 2:28 am, Keep Connect reset…I never would have noticed?

I am very suspicious that there is something going on with the cellular system where the grey cylinder loses lock, and the symptom we see is the internet down, and we need to do a reset.  I went months after adding a fan, without failure, or did I miss the middle of the night failures?

Just wanted to update this saga, I am very pleased that Keep Connect, bought on Amazon, automatically detects problem, and does a reset, but what is causing the real problem.  Every time I have had the internet go down, a simple power off for 30 seconds has brought it immediately back on.

thoughts?