Options to improve digital sound

@mihorn 

"All current digital players and DACs sound veiled/glared."

Interesting. So how long did it take to listen to every digital player and DAC?

Great system. You are short on one aspect. A high quality streamer. It should be at the same level as your DAC,  Preamp or amp. Given your system I would recommend an Aurender N200 or Aurender N250. These would provide the level of performance commiserate with the rest of your system. 

I spent several years refusing to invest in a good streamer because it was basically the same thing as my MacBook or PC. That was one of the biggest mistakes I have ever made in audio. I completely wasted the time with grossly inferior sound quality. The sound quality of your CDs should equal the sound quality of stored files and streaming. However, Qobuz  should sound  better with their one half million high resolution albums.

A good streamer must be built with the same dedication to detail, and quality that any other audio component has to be. It needs an outstanding power supply, internally and externally shielding from noise, vibration... etc. This requires lots of design time, high quality parts and expertise. Aurender makes some of the best streamers... it is all they do. After owning a dozen other streamers over twenty years, I own two Aurender. My vinyl playback, CD, stored files and streaming all sound the same, the best sound I have every had.  You can see my virtual systems under my user ID. 

I went through three Mac minis with various diy modifications, the two most effective were mod to operating systems, shutting down unneeded services, the other was adding LPS with Uptone JS-2 and MMK. So this one route and you'd have a pretty nice streamer at this point. 

I like the idea of adding an Endpoint, Roon sound quality improved running Core on one streamer, Endpoint on something like the UltraRendu. I use the OpticalRendu finding optical conversion worthwhile. The problem with this is you won't hear the full potential of the Endpoint with your mini in present state.

So, if not into diy mods with present mini, and I don't really like your mini as I believe it has soldered RAM (RAM upgrades another worthwhile mod), I'd suggest a new streamer The SonicTransporter  I7 is a very nice streamer at that price point, remember you'll also have to invest in a 12v 4 amp linear power supply to power it. SGC has their own, the other options I'd suggest are likely over your budget. And then sometime in the future you could add something like Ultra or OpticalRendu for even further improvements. 

Nice system! I think your best bet is to add a Roon endpoint between the Mac and the May. This isolates a lot of the noisy processing required by Roon. You will get a lot of recommendations for endpoints, I have had good luck with Innuos. Check out the used market, you can get some good deals. And be sure to allow in your budget a good digital cable connection between the endpoint and your DAC.