Help me out with streaming...

+1 to using a dedicated streamer. The Mac Mini can still be used solely as the server.

You are experiencing a major bottleneck by using USB straight off the Mini’s motherboard. The H190 has streaming capability, so I recommend connecting the H190 to your network over ethernet. Then stream from the Mac Mini to H190 over UPnP. As long as the Mac Mini and H190 are on the same network it should work. This will accomplish a few things.

1) Separating server and streamer duties to separate devices

2) Connecting these devices over a network electrically isolates them

3) The streamer can be a low power and low noise device feeding into the DAC

OP

You can get get sound from a computer with Audirvana Plus.  I prefer streamers but my recommendation is get a streamer on trial, put it in the same system, and compare

+Sonic79. Another thing you can do is bridge the thunderbolt out on mini as ethernet out, this link explains exactly how to do it, big upgrade! https://audiophilestyle.com/forums/topic/30376-a-novel-way-to-massively-improve-the-sq-of-computer-audio-streaming/#comment-613370

Wow thanks guys!!!