So I found this PDF that seems to be pretty clear that Z4s model year 2019 and later with Live Cockpit Pro could have the Drive Recorder capability if option 6DR is ordered. I couldn't find that option in the ordering guide for G29s!
Oh well, it would have been a major surprise if all we had to do was buy it as a ConnectedDrive app. Maybe at some point that option will be available as a dealer installed option.