Streaming

+1 for the Node 1.

The cheap option- correction, the inexpensive option is a Bluesound Node. If you don't need wireless connectivity, just get any model. The Node 1 (cube shape) does what all the Nodes do, and can be had used for almost nothing. All you have to do is upgrade the firmware/ app.
The higher priced option is to go with an Aurender-though you are limited to Tidal and Qobuz. You'll get a more refined listening experience from the Aurender, but the Bluesound is no slouch, esp. for the money.
There are other streamers, but I have no experience with them.
Bob

You should probably mention what your budget would be for a standalone network streamer. Also, there are many AVRs that include support for streaming Tidal, which might be the easiest approach for you considering you are already using an older AVR.