Striving to understand the landscape of digital and streaming audio

[feelingears]

It seems you have enough already given your goals. 

 

In my experience your hard drive music files in ALAC are excellent via iTunes...until you try to get them off the computer. The diagram you want would show a decision here for USB or Ethernet or WiFi. The trade off is quality vs convenience vs affordability. Choose two (kidding, sort of).

 

Since ultimate sound is not a goal, then your physical layout needs will inform your choices as well as minimize/avoid additional expense in the form of quality improving power supplies. 

 

I don’t stream so I’m no help, but everybody here (figuratively) seems to think Roon is a god-send. If that were an option and quality is desired, you have many options to spend money! The good news is that there are reasonably priced upgrades for the “endpoints” of your signal that feed your DAC. 

 

This is one possibility; hope this helps.