A few more tests to share...
On a drive to a restaurant, I called my voicemail. It connected fine, but it could only understand 1 or 2 digits of my 4 digit code. I tried repeatedly. I finally hung up.
Once at the restaurant, I tried several calls to my voicemail. It did connect every time and it did understand all digits of my code. However, it took several seconds to connect each time. I noticed that it would be on LTE before I'd call, but when I would call, it would try LTE for a while and then give up and try some other protocol and work.
Oh, and I tried speed tests bo