Apple TV (the TV app on the Mac, as opposed to the Apple TV hardware) output supposedly works, although I haven’t tried it. That would allow video content from Apple with Atmos to go to Virtuoso on a Mac. Loopback (or blackhole) introduces some latency, so you might have to futz with audio delay if bad lip syncing drives you crazy (like me).
I just read that Plex on OSX will work too, so I’ll add that to my list of stuff to try this week (I have plenty of MKV movies and TV on my Plex server, but none with spatial audio, just 5.1 - I’ll rip an Atmos disk to try).