iPhone 16 Pro - Software/Hardware issues iOS 18.0.1

So I recently purchased the iPhone 16 pro through apple direct on Sept 26th.

Shipped on 10/6, had it for a week, and ran into screen freezing, phone automatically restarting.

I took this to the Apple Store, ran diagnostic tests and through apple conclusion, provided a SWAP, couldn't fix on site.

Whether it was hardware or software issue, I was given another device.

A week after getting the SWAP device, again, the phone automatically restarting, screen layout looked fragmented. I go to the Apple Store 2nd time, again, ran its diagnostics test and swap the phone out again.

This time, apple is telling me you downloaded a "beta" update, even though my settings have beta turned off, never used them or plan to.

Really confused on the real culprit to this issue, already have performed troubleshooting steps prior to visiting Apple Store. Is anyone else running into the same problem?