That sounds very strange, however can you please check in Settings > Network & Internet > Mobile networks and see if you have an setting here called "VoLTE"? It usually says "Use VoLTE when the service is available".
If you have it and it's turned on, can you please try and turn it off and ask someone to call you while leaving the device on 4G and see if you can receive the call or not.
If it still doesn't work, do you have a colleague, family member or friend that has a Nano SIM card in their device that you can try in your device and see if you then can receive calls while on 4G?
Let me know how it goes!
@HarleQueen, sorry for the very late reply to your post, I have been out of office due to vacation and being sick.
Could you please try what I suggested to @alkemyst and see if that helps?