A bit of an update on the ProJect Streambox S2 Ultra... I spent a good part of my morning attempting to disable the bluetooth connection as it was not secured. I eventually gave up and reflashed the Streambox with dietpi, I wouldn't recommend this task if you are not comfortable with Linux, but there's plenty of help available in various forums.
Now my custom box is running dietpi and my music collection is accessed with emby, a very slick interface. Audio quality is superb, temps of the box are lower.
Most of my music files are flac's with some dsd thrown in as well, all sound great. Now to rip my remaining cd's.