Hello!
Unfortunately I had to sell my Camaro and get something more practical (truck).
But hopefully I can help by clarifying.
Removing the Cellular modem in my 2019 base model did the following:
* Disables all On-Star functionality (including the annoying *CONNECTED TO ON START LIMITED SERVICES voice prompt that happens randomly when you start the car) meaning the car is no longer on the internet.
* Disables the microphone in the car.
What you can still do:
* Use Bluetooth audio streaming (Phone, Tablet, etc)
* Android Auto & Apple CarPlay (Siri and Google Assistant will not work because the microphone doesn't work)
* All other standard radio functions (AM/FM, USB)
What I couldn't test (because my car was not equipped):
* XM Radio
* Navigation
^ These features will likely not work properly. From other forums the navigation may work for a brief time but it will eventually become out of sync with your location.
In my case, removing the Cellular Modem means following the guide above to remove the chip that has the E-Sim embedded (what the antennas attach to) but leaving the actual On-Star module plugged into the car's wire harness. I stored the chip in my office desk drawer the entire time I owned the car and I never had an issue.
Let me know if you have any questions. I can try to answer to the best of my knowledge.
