Chosen Solution

I have reset the phone multiple times and tried it on multiple carriers. It will sucessfully place the call, and the receiving party can anwser the call. There is no option to change audio source, usually the top right button in a call.

The iPhone 7 series of devices have proven to be very unreliable, suffering from flex-based issues similar to the iPhone 6 Plus (Touch Disease). On the iPhone 7, the fault line runs along the top of the SIM card reader and affects the Baseband CPU and Audio IC. There are a few copper traces running perpendicular to the fault line that connect to the Audio IC that are subject to failing. Here are the typical symptoms, as collated by the repair community: Voice Memos app / Loudspeaker on call - greyed outSiri doesn’t hear you / Caller can’t hear youMost other Audio related issues that aren’t solved by modular replacementsLong boot times (3-5 minutes)iTunes detects the phone but stuck on the Apple Logo This requires a micro-soldering repair and is not a DIY fix.