Hi there… I am in the same boat as you. So far the onlyway that I can see of doing anything like this is to install Plexamp for Raspberry Pi following Elan’s instructions here: Plexamp for Raspberry Pi Release Notes.
The only problem is that it looks like it nukes the DietPi software that is already installed. I haven’t plucked up the courage to do it yet as it’ll be a right pain getting DietPi back on there, set up the way I like it.
Would love to hear back if you get it working though!
Cheers, Bob