Digital streaming options for my system are confusing

Bluesound Node 2 or 2i is an excellent choice.  Wireless connection with simple setup provided in the BluOS app.  Use your phone or tablet for control.  Link for Tidal subscription is in the BluOS app.  You also get for free, Radio Paradise and hundreds of internet radio stations.

Connection to your Mac can be rca from the Node to an input on the Mac or if you want to try the internal dac in the Mac a digital cable is required between Node and Mac.  Both can be connected at the same time so you can toggle inputs on the Mac to see if you prefer the Nodes internal dac or the one in your Mac.

 I have the Node 2i and am very much impressed with it.

Note: you will lose MQA decoding using your built in dac.  So, use both connections as I posted earlier.  
You can also play via Bluetooth from your phone.

The Node 2i has both analog and digital outputs.  The simplest connection is rca cables from the analog outputs of the Node to any input on your Mac.  You now have music playing.
This connection is using the internal dac of the Node and allows hi Rez audio files to be played via MQA decoding from Tidal.
A separate digital only (just the 1’s and 0’s) connection using a digital cable (could be optical or rca) to your Mac’s built in dac will also play music but will not unfold MQA files from Tidal.
You can have both connected at the same time and switch source inputs on the Mac to see which you prefer.
Neither choice has anything to do with the amplifier output.