Phone: Galaxy Z fold 5 Unlocked verison bought in USA. 
Carrier: Airtel - India 
Sim slots tested: Physical sim and eSim
Affects: Calls, messages and mobile data is unusable.
Issue:
After System Update the phone is showing emergency calls only or No service.
Tested scenarios:
1. Changed physical sim
2. Converted to eSim.
3. Did factory reset device
4. wipe cache partition