IPhone 12 mini: Signal loss and call drops continue..

Folks, I have had this problem since I bought it in April. Calls drop out. I can hear them and they can't hear me. Sometimes I suddenly can't hear them and have to call them back. Or, people say they tried to call and got nothing.

It happens at home and on the road. I have a 5G tower nearby. I have a 5G capable phone

I've opened cases with AT&T. I've opened cases with Apple Tech support. I logged and complaint at the issues site. They all act like they have never heard of such an issue. Yet, I have read about it on numerous forums including this one.

I've tried all the fixes listed here and at other sites some dozens of times. Resets, Airplane mode, Reset Network settings, turning off 5G, etc., etc., etc. Nothing works. I'm sorry I bought this phone. I've had some health issues and nothing is worse than a call from a doctor dropping out. And hearing them say, "Are you there?"

Why is this not being addressed? Are there any NEW fixes or solutions I may have missed?