Looking for equipment/setup recommendations for 2 channel audio streaming

Have been away from good hifi for a while, have some equipment, and would like to step it up a bit.  I have some B&W 702 S2's driving into a less-than-optimal living room. but with good seating for 4-5, 15 feet away.  I can live with the open floor plan living area with occasionally groups of people not really listening anyway.  I'm trying to keep it simple, -  more absorbed by the music than by the sound, and I mention this because it seems to be a thread that runs throughout Audiogon discussions. I'm a find-your-personal-balance guy.

I now have the Sonos Connect handling the streaming via both Tidal and Qobuz (currently deciding on my preference) and using a vintage old favorite Rotel RB 956 AX bi-wired to the speakers. A good quality ethernet line ties it together. Sonos allows me to choose music from my library and from the streamers and still listen to Play:1's outside in a sitting area outside.

It's the amplification and the quality of the DAC capability that I am questioning, and would be happy to hear some readers' thoughts on making changes here. I would make one change at a time as convinced. 

I have no problem with used equipment except for my own knowledge base at this point.  My listening history begins with Acoustic Research speakers, amps, turntables, some very happy years with a good listening room and Martin Logan ESL's and then a period of being turned off by theater and multi channel sound generally.