incoming calls and sms issues with ios 14.3

I am using iPhone XR with IOS 14.3 version.

I see issues with, receiving SMS / OTP from specific carriers or applications (observed this behavior with Reliance and PayTM ).

Most of the time the person who calls me is hearing not reachable or switched off.

When I try to make a call I have to turn off the WiFi for a better calling experience sometimes call will not go at all though the signal strength is full and good.

I don't this behavior when placing the same sim in a normal phone or android phone and the phone always shows good single strength and 4G network.

Is this issue with IOS 14.3 version or do I need to do any specific settings?