What has Victrola’s customer support said?
I have the Victrola Stream Onyx and my wife and I use it daily. It was a bit confusing at first because it does not show up at all in the Sonos app, and it is not supposed to.


You will select the speaker on which you want to play in the Victrola app, not the SONOS app. I have my Victrola set to Autoplay to DEN, which is set to be the default speaker in the Victrola app. Once the connection is made, you can return to the SONOS app to change speaker, group speakers, and adjust volume. You can also adjust volume using the knob on the turn table.
It also may be worth noting that DEN, in my case, is my home theater setup. My Tv is also set to auto play in the Sonos app, so if the tv is on, even with a screen saver, the Victrola has a hard time connecting because the arc is getting conflicting signals. That also caused minor frustration until I figured out what was happening. Bottom line, if you select your home theater the autoplay Target for Victrola, make sure the TV is powered off.
Drawing a blank on where but I think there is an option to play another source on the soundbar with the TV on. We used to use that to watch fireplace videos with a Christmas Playlist providing sound instead of the TV.
Remembered under Settings Home Theater Autoplay.
Thanks, @Stanley_4 . I do have that toggled in the app, and it works perfectly for other music sources, so we can do as you described and have fireplace/art images on tv while playing music. I just find that the arc is inconsistent with Victrola taking over when tv is also on. I usually find it faster to target another speaker first. Then, using the SONOS app, I change the speaker over to the arc. Who knows, perhaps it is because the Victrola does not show a an actual source in the SONOS app?