I have a pretty stable setup with a headless Mac Mini connected over USB to my Aqua Formula DAC. The DAC shows up as a Core Audio device.
I use a Luna dongle to wirelessly send the display output to my iPad and that all works pretty well so that I can stream from anything on the Mini, YouTube, Naxos, whatever.
Is there a compelling reason to upgrade to a new Mac Mini? It is certainly nice that the line has been refreshed, I’m just wondering what I will gain.