The Bluesound is always a solid starting point. But here is an alternative that is even cheaper way to dip your toe in the streaming waters (pun intended). Over on www.usaudiomart.com there is a SONOS Gen 1 Connect that has been modified by Wyred4Sound for digital out. Sonos still offers the Gen1 controller app. These are solid units and sound purdy good. I have had one for many years and the thing has been rock solid. You could go Coax from the Connect to the Digital in on the Yamaha pre. The price on the Connect is $200 but its been over there for several months and I bet they would entertain a little less. I still use my Sonos W4S ZP90 as a ROON endpoint on a secondary system and it works great. Then you can explore you upgrade path while have a rock bottom startup cost.
Darko Review from years ago.