iPhone 16 pro has very poor incoming call service - first responder

I'm a first responder and I NEED to be able to communicate. Both my wife and I had previous versions of iPhones including a 13 and and 14. I recently upgraded to an iPhone 16 Pro. The phone has zero ability to make outgoing calls. We do have somewhat poor reception where I live, but the other phones work fine. It's apparently an iPhone 16 issue. I am on the First Net service, but it should be called No Net service! There use to be an option to use "WiFi Calling," but that feature has been removed.

Anyone else had this problem? Need help ASAP or will need to return phone. Thanks.