You can add a pair of Ones as surrounds to the Ray to create a 5.0 home theater setup:
https://support.sonos.com/s/article/2927
Or you can group the speakers in the Sonos app to play the same music (from Spotify or any other music streaming service) out of all of the speakers:
https://support.sonos.com/s/article/3391
I’ve recently added a Ray to a small TV, alongside pair of Sonos One SL’s that were already in our Kitchen/Diner and it’s made a big difference. The small TV now feels/sounds like a much larger HT setup.
The music output with speakers set to ‘Full’ audio for music is great, (we’re using Amazon Music) - it really surprised me how much sound can come from such a small soundbar.
I have a (new) Sub-Mini which I’m currently using in the Bedroom with the Beam (gen1) and so I tried that small Sub with the Ray HT and that is really fantastic - so a second Sub-Mini is in my sights, but SWMBO says I have a lot of dishes between now and Christmas to wash-up before that ‘might’ happen.
Sonos soundbars work for music in exactly the same way as other Sonos speakers. As others have commented, if you have surrounds then they can also be made to play in full stereo.