I'm using Audirvana (with Qobuz) and HQPlayer Desktop on the same machine (M1 MacBook Air). This worked for me:
1. Download and install BlackHole (I chose the 2channel option because I only listen stereo)
2. In Audirvana, set output device to Blackhole
3. In Audirvrana audio settings, set Exclusive Acces OFF, Large CoreAudio I/O buffer OFF.
4. In HQPlayer Desktop, set input to CoreAudio, device to BlackHole
5. In the source path, enter audio:default/44100/2
6. Click on the single empty track line that appears, to start conversion of the blackhole stream bij HQPlayer
7. Start playing in Audirvana. Voila!
As mentioned, HQplayer sees everything as a 44,1kHz audio stream from that point, and streaming other sample rates won't work (I figured this out when a 48kHz version of Bruckner 8 was playing a semitone too low and conspicuously slow...).
It's interesting, but has limitations. You can manually change the source path to audio:default/96000/2 etc, but on this laptop, results get inconsistent (probably a buffering thing from both sides, Audirvana and HQPlayer). Of course, you can also convert all higher sample rates to redbook in Audirvana, but that defeats the purpose for me. So I only use it for redbook content.