You have everything. Go to Jriver and play files that are on your mac. Usb cable from mac to your dac. You can also subscribe to streaming services such as Tidal and play directly from Tidal to your dac
The Sony is a proprietary server that only plays it's own file format. I won't go that route. The MackBook Pro is an excellent PC to use as a server/renderer. I have the PS Audio NuWave DSD DAC and find it to be an exceptional DAC. I would include an optimization program in the Mac to really help in SQ. A LPS is a big deal with CA. I'm to a point that is much better than I've ever heard with a CD player. Good luck.
Pretty simple to do, although there are several options.
I run a headless Mac Mini, USB out to a PS Audio DirectStream DAC. My main library is stored in an iTunes library on an external Firewire disc. (The USB goes into an Uptone Audio Regen first.)
iTunes is not the best way to play, though. You'd want something like JRiver, Amarra, or as in my case, PureMusic to actually take on the signal processing.
Another option that I employ is to run Roon, but I'd suggest getting the above to work first. Roon seamlessly integrates Tidal (subscription needed) with your iTunes library.
Lots of information on various setups can be found here on Agon.
Matt00, there's no agreement of which program works best, but the most commonly uses ones have all been mentioned; Audirvana+, Pure Music and Amarra for Mac. Jriver for mostly windows, and recently added for Mac.
With one of those instead of iTunes from USB to your dac, you are well on your way, but not yet the best SQ.
The two big themes are power supply noise and USB noise. A million threads, cables, tweaks etc all point to cleaner power and more isolated quieter signal. With USB carrying both signal and power in a little cable and one connector there are many challenges being tackled by all kinds of approaches. Computeraudiophile.com discusses them in more detail than is typical here, but if you invest a little research time you will get up to speed quickly. Cheers,
Unless you want your program to alter/process music (like upsampling) playback program should not matter with asynchronous USB since there is no timing in this scheme (data sent in packets).
Computer noise is always important since it affect DAC's noise. USB cable should have only data wires - power should not be delivered to DAC from the computer.