Do I Need a Dedicated Streamer?

I found that moving from my laptop to an Aurender streamer was revelatory in the positive improvement in sound. It wasn’t close. Hardwire the server with Ethernet.

 getting good results with the Bluesound Node in my second system, again with a hardwired Ethernet connection.

Finally, try hirez Quboz- I never listen to my records anymore as it is better (on my system).

Gotta love those people who argue over Ethernet cables, the dismiss WiFi that removes them completely from the equation. Or that are concerned about jitter on their Ethernet connections. They're still very confused about TCP/IP. FWIW, buffers eliminate jitter. If jitter is so bad that the buffers overflow, then there's a serious ssue with the network that would show up in the router management as dropped frames. 

Unless you are serious about cobbling a streamer from a Raspberry Pi, and doing the associated bit-twiddling, just get a BlueSound Node. They're available for under $500 now, and a big step up from your current setup, and not that far behind the $3k to $5k offerings. Next get off of Apple, whether you move to Qobuz, Tidal, or Amazon UHD. You'll be very pleased. 

Logic dictates that your source be at a commensurate level with your amp and speakers otherwise it is the weakest link in the chain and will not maximize the amp and speaker’s sonic capabilities.

Just set aside all the comments here and think through that for a bit for yourself... you spent big money on your rig so far for a reason, you wanted the best sound you could afford, so don’t sell your rig short.

Here are 3 excellent streamer choices at ascending price points that have internal DACs and USB outputs so you can utilize your amp’s internal DAC as well:

Eversolo DMP-A8

Lumin T3

Aurender A15

Phones r good as remote controls for dedicated streamers. 

I suppose that I could wire my mac mini using a usb cable to my Hegel and get streamer level quality without buying a dedicated device?

Try it. What do you have to lose if you already have the Mini? I've used this setup (with different amps/DACs) and it works fine.  You can host Roon Core on a Mini (or other full-function computer) as well as Audirvana or (of course) Apple Music.  Turn off Time Machine (or schedule it to run at night) and other process that might interrupt the music stream.

In my opinion, your choice of streaming platform may be best dictated by the services you want it to support and how you want to control it. With a full-function computer (like the Mini) you have many options.  After you've experimented with a few, down the road you might want to add a dedicated streamer.  If by then you've decided (for example) you like Roon, you can focus on Roon-Ready streaming devices.  In that case, one of the Rendu products would be an option;  Aurender (at this time) would not be.