Digital streaming options for my system are confusing

Another Vote for Bluesound.  It sounds great in a high end system, I wouldn’t let old fashioned High End Dealer snobbery persuade you otherwise.
  May I ask the OP—how many 32 bit recordings do you own?

I don’t know wher high end starts but my node 2 sounds wonderful through my KEF R900’s. If that’s midfi, then I’ll take two!  😼

I can wholeheartedly recommended Bluesound. I have the Vault 2 but if you do not need or want CD ripping ability then the Node 2 or latest 2i should work.
One other point on the Vault is that it takes hard wired internet only where the Nodes take wireless.

I used to run my Vault via spdif into McIntosh c48 pre which has very similar DAC to the mac6700 although possibly a generation earlier.

It sounded stunning is best word for it.
Have since moved on many times on amps, DAC etc but still have the Vault as to better it I know I need spend a LOT more than the $1050 it cost me couple years back.

Another vote for Node 2. The newest version is the Node2i. If you get a Bluesound and stream Tidal and the MQA albums, you might be surprised at the quality of sound. Auralic, Lumin and Innuous have some high quality offerings but I have found NAD and Bluesound are really dedicated to customer support. To me customer support often gets overlooked when choosing brands. Some companies and dealers promise the world when you pay top dollar for the gear, but fall short with delivering service. I have had stellar IT support for networking issues with the modestly priced Node 2.

What he said.