Interesting. It would be instructive to test this in lab conditions with Primare or WiiM endpoints. I recall someone who set up Chromecasting based on Google's documentation as well as other data. Not a big deal for me, however, since I think potentially Apple or Amazon may be the better strategic choices than Qobuz -- or Spotify, if they figure out how to stream CD-or-higher quality without reaming their customers -- even though I like the Qobuz's service quite a bit.
Separately, I wonder if you've done network traces on the Pro and whether any data from the microphone is sent outside your local network (e.g., to China or elsewhere). I plan to put my devices on an isolated VLAN and look at network activity very carefully -- and continue to do so, given that the devices will get firmware updates fairly frequently, which could change how they behave. Just wondering if any processing is done off-site.