Thanks for all the input in trying to troubleshoot. It was exactly the same time as I switched phones that I started having these issues, but the dealer confirmed today that there's a defect in the radio unit. There's not a piece of software that can fix it so I'm staring at $12xx to replace it by the dealer. It's the 8.4 nav.
There only two options that I can see: 1) buy a second hand (which I'm guessing needs to be married to the vehicle by the dealer) or 2) buy the 13.6" from Phoenix Automotive. For the price, I'm obviously leaning towards option 2 because it's $700 for a huge, but there's quirks with it that I'm not sure about yet.