I broke my radio and did not know it.
I had a bad sim card that confounded the issue. The new sim made things better but still unsteady 4g and on EHRPD. Then I found this info on a Russian site:
*#*#4636#*#* OR the Play apps: Phone Info will break the radio IF you select the 3 dots and mess with the band!!
RSD flash or Matts utility is the only fix. Flash of a new radio did not work.
Source
Dear Moderator: please delete the external link if need be.
This should be a sticky!