I hope that someone can help me.

I have used Spotify for a long time but I am currently experimenting with YouTube Premium and may well settle on the latter. Part of the reason for this is that I can listen to YT videos via a Chromecast audio on the line-in to my ZP90. I think that Sonos will play albums from YT Music just as it will from Spotify but not the audio track of videos.  Of particular interest to me are videos of live music that are not available as albums, for example Hania Rani live at Invalides, in Paris, France for Cercle.

I can do this from my PC provided that I use Chrome rather  than Firefox, my preferred browser, but this only finds the CCa (and TV and Roku) and not Sonos but will thus play through Sonos, although seems to be subject to drop outs which is very annoying. (That may be a fault with the CCa, although I suspect it is something else)

However my Android phone using the YT app will only find the TV and Roku but not the Chromecast or Sonos.  Spotify on PC and phone will find all 4 of my Sonos units (ZP 90 and 120, Play 1 and Playbar) as well as the CCa and will connect directly but it appears that YT have no such facility. Of course, Spotify has no access to videos on YT so cannot play these at all.

Is there a way though this?

As a separate issue, I find little difference between the sound quality of the two services despite differing bit rates, although my defective hearing may be part of the reason for this.