I was having the same problem a lot of other people were with connecting to my Sonos once I installed Google WiFi. As best as I can work out, the problem is due to the controller apps using broadcast traffic and that Google WiFi actually creates a separate network and routes traffic between the WiFi network and the local LAN network.
Now that I have solid WiFi across the house, the answer is fairly simple. You need to connect the Sonos systems to the WiFi rather than the LAN cable.
If you already have Sonos setup,
1. Use the desktop application to go into each of the "rooms"
2. Right click the room and select settings
3. Select advanaced
4. You should now have the option to connect your system to the Wireless network. Put your details in to connect to your Google WiFi
5. (I don't understand why these steps are needed, but seemed required to finish the process) - Disconnect the network cable from the Sonos controlled
6. Press the advertise combination, eg mute button and the increase volume
Worked for me, hopefully it will work for you