Peachtree Nova 300 inputs

I have a Peachtree Nova 300 however the sound I get playing the same source - Qobuz - delivers remarkably different results between the following connections.

1. Sonos Connect with volume bypass via Audioquest Optical to Nova
2. Bluesound Node 2 via Audioquest Coax to Nova
3. iPhone via USB on Nova using bog standard Apple lightning to USB cable.

To my surprise 1 and 2 sound remarkably similar, but 3 outshines them both by a country mile. Much more detail and openness. A WTF moment...

I am currently playing with Roon as the UI, and ideally would like to avoid having to plug my phone in to play music...

Any suggestions/ideas of what to tweak please?