iPhone 17 Pro Max, dropping calls and wi-Fi possible reason?

I have a family member that’s very much trained and networking, and he came over yesterday. My brand-new iPhone 17 Pro Max only connects to a 5 GHz network that is until I step within 5 to 10 feet of our router. If I reboot the Wi-Fi on my phone within 10 feet of my router, it will automatically connect to 6 GHz., and stays connected to 6 GHz. Once I walk away to about 15 feet, it disconnects totally, 100% no Wi-Fi, then reconnects to 5 GHz. I have two other iPhone16 Pro Max in the house that have zero issues and stay connected to 6 GHz. No matter how far I am from the router. I believe this is an issue with a faulty antenna on my iPhone. This also answers the possible issue with the several drop calls I’ve had in the several days.

I believe there is a problem with the installation/manufacturing of the new antenna design.