iPhone shows No Service even after Factory Reset

My iPhone 11 is showing No Service for the last 10 days. There was no physical damage or falling down, but the phone suddenly started showing no service. Even after changing multiple SIM cards, it still shows the same.

Its been 1.5 years since I bought the new iPhone 11. It is not covered under warranty.

I have contacted Apple Support and tried all the steps below:

1. Restarting the device
2. Reset Network Settings
3. Replaced SIM card from carrier with new one. This SIM card is working on other phones
4. Apple Support team ran diagnostics. They took 3 days to review the logs and confirmed that there is no physical damage
5. They asked me do a factory reset and setup the phone as new device. Even after formatting and setting up as new device, its still the same issue.

Apple has not been responding. Is there anyone who had similar issue? Can anyone help please?