Not sure that's possible. Sync is a Bluetooth device. I don't think it's plays as a Bluetooth controller. Another area I'd love to be wrong because it would make typing in navigation a hell of a lot easier to use this old BT thumb keyboard I have in a drawer somewhere.
You can pair phones and supposedly other Sync-compatible Bluetooth devices. I tried pairing a Logitech K380 keyboard, but Sync said there was no Sync support for the device.
I'm wondering if there is a firmware patch, dongle, or special keyboard? Maybe FORScan (not familiar with this at all)? I highly doubt Sync developers and testers are testing by tapping screens 8 hours/day.
I don't have a USB-C keyboard. Someone else can try theirs?
That said, today, the tech at my dealer said "I wish!" when I asked him whether a physical keyboard could be paired with Sync, so at the very least, we know that dealers probably don't have this information.