Garmin OTR810 does not support music audio

Bought Garmin OTR810 ($700). Use Blueparrot B450-xt headset. Bluetooth android phone and OTR810 to headset. Playing SiriusXM on phone and hear music in headset. BUT, can't hear garmin voice navigation prompts. They work but only through OTR810 speaker and not headset. Disconnect the Bluetooth phone from headset. Can now hear garmin voice navigation prompts. BUT, no longer hear SiriusXM music.
Called garmin and the said they don't support music audio (I think A2DP). However, you can see the audio controls, and title artwork on OTR810 and control the music. Just no audio. What genius decided that was okay.

REALLY? The latest ($700) model and doesn't support "multi-mode" bluetooth. Buyer beware.

The OTR810 seems to function fine otherwise after the learning curve of all the controls.