I’m thinking of something very similar. The using an amplifier that can also function as a Roon core and feeding it with music that’s on the mobile phone with the same mobile phone being the actual remote with which you start the music. You have gone through something like this? I would love to do this wirelessly, but Roon does not recognise the phone. Once it is connected to the amp via USB it should work? I have not gone out and bought this set up yet therefore my fairly silly question.