I use Apple Music as my streaming source. I use AirPlay from my iPad or Chromecast from my Android phone. Chromecast sounds better. My streamer is Cambridge Audio CXN 60.
I didn’t get what amp the OP is using. For silver disc replay connect the disc spinner to the same DAC you use with the streamer, or else just run it directly into the amp, if you prefer the internet DAC of the disk spinner.
I didn’t address Roon here, because I don’t use it. Frankly, Apple has co-opted so many of the Roon features, I think Roon is a waste, and you may lose access to some of the Apple Spatial Audio offerings. If Roon is essential, then get a streamer that handles it.
You can use a Mini for all of this, but a dedicated streamer will sound better and leave you less at the Mercy of Apple updates, which tend to to mess up interfaces with non Apple equipment