Thank you all very much for sharing your experiences with me.
While the 150b has some incredibly great sound-quality, the interface isn't working as expected for me. I see on their website that others have complained as well (Qobuz, especially). I've had it for over a month but finally gave up so I asked the questions here.
After posting here, I spent two more days on it (about 18 hours each day), just playing and experimenting: the issues persisted. So it's definitely going back. Maybe I received a brick. But I've had enough.
I also really dislike that I put my dealer through an ordeal because he'd never run in to issues like this before.