We have already added AC-4 support to our app for a number of platforms and devices, and continue to work on enabling more devices. Many additional devices without AC-4 support can also add an HDMI soundbar (or AVR) with AC-4 support.
Clients that can't support AC-4 will still be able to tune ATSC 1.0 channels, once we get that feature fully implemented (technically they can tune them now using a URL, but obviously we want to make it easier than that).
This will be no different than any other ATSC 3.0-based product. If you get an ATSC 3.0 USB tuner then you will be faced with the exact same codec requirements.