Not to hijack the conversation but, I have a 2015 Audi that originally had an AT&T SIM and access to their 3G network. I replaced that AT&T SIM with a pay as you go TruPhone SIM, much cheaper than AT&T and and things worked great. (real time Google maps data, search, weather, etc.). The car is not 4G LTE capable to my knowledge. I assume that with all of these 3G networks shutting down I’ll be SOL with respect to data service. I’ll have to ping Audi to see what they say.
EDIT:
So, I got my answer buried deeply on Audi’s website.
All Audi connect services will no longer be available following AT&T’s 3G turndown on 2/22/22.
Impacted services include:
Google Voice Search, Weather, Fuel Prices, Travel information, Flight information, Parking information, Point-of-interest search, and Wi-Fi hotspot.