Streaming For Beginners

No USB inputs. 

The simplest, least expensive way to begin is with a Bluetooth receiver plugged into one of the analog inputs on your amp. That will let you test the concept using Spotify, Pandora, Amazon Music, internet radio and other sources. The quality of Bluetooth transmission isn’t what you get from a CD but it may be good enough for awhile, particularly if you pick a receiver with aptX HD built in. One of my friends with a full McIntosh stack and Nola speakers is quite happy with a $149 Bluetooth receiver for casual listening.

Pick one with good customer reviews from this page in your price range and give it a try. https://amzn.to/38p3kMc

If you pick one with digital output you could add a DAC between it and the amp to improve the sound but I wouldn't spend a lot of money on that solution rather than moving to a streamer that would use WiFi rather than Bluetooth.

I have a good dac, and don’t really want to pay for the dac in devices like the Bluesound Node 2, or a $5K+ Lumin;  Is it correct that all I would need to get Tidal and Qobuz is something like a $70 “KEiiD WiFi & Bluetooth (CSR 5.0) Wireless Stereo Receiver for 2.0/2.1 Home Audio System Optical S/PDIF“?  Anything better at a reasonable price?

For a Few Dollars More.  You could get a Schiit Modi for $99.  Then you could go USB out of a tablet or laptop to the Modi then analog into the Sherwood.  That opens up the option of doing a Trial subscription to Tidal or Qobuz and testing higher resolution content up to 24/192. If you have eclectic music tastes you can stream Radio Paradise FLAC 16/48 for free through a browser tab. 

No knowledge of the KeiiD WiFi receiver but considering its price and reviews if you want to stream from a phone or tablet it's worth a try, especially since you can easily return it to Amazon if it doesn't work.