I'm not surprised that I can't play the music in my local (NAS) library with the new GA/Sonos integration. However, is it also not possible to play music that I've uploaded to my Google Music account? I can do this using the Sonos app.
If I try "Hey Google, play (artist) in the office" I get "OK (artist) from Google Play Music playing in the office. Sorry looks like the subscription tier for Google Music is not supported." I've also added "from my library" to the command and that doesn't help.