Thanks to all for your input and recommendations. ATT escalated and I have not heard back after 3 days. Spent an hour on the phone with apple and they recommended I backup and factory reset which I did not do. I decided to turn on wifi calling while connected to my home wifi just hoping to get some of the important messages when I am at home. Group messages, text alerts, and two factor authorization started working immediately. Disconnected from WiFi calling and everything continued to work fine afterwards. About 24 hours later I received all 112 missed group messages, text alerts and authorization codes from the past couple of days.
If you read the description of 14.3 it is supposed to be a fix for this issue caused by earlier versions of 14. Funny how 14.3 actually caused the issue for my two phones and countless others who never had the problem. Cannot see how this isn’t an Apple issue.
Anyway, hopefully this is helpful to others who are having this issue.