Tacx Training Desktop, Flux S and VO2 Max / Training Status

Hi all,

I use the Tacx Training App (on PC, not Phone)  with a Tacx Flux S and a HRM-Strap. To my understanding, it should be possible for Garmin Connect to calculate my VO2 Max and Training Status. I also use a Fenix 7S since a few weeks which automatically syncs with GarminConnect. However, nothing happens: Only those activities seem to count towards VO2 Max/Training Status which are directly recorded on the watch. Am I missing something or is it simply not possible to use Tacx Training Rides for VO2 Max/Training Status?

Thanks!