Best answer by ratty
Yes! Do this. Which switch is it by the way? Most should be okay but if it's managed it may need a tweak to its config.
Will the Sonos components automatically understand that Sonos inter-communication should go through the wires?
It will favour the wired path where it can. Wireless units will connect to whichever wired unit offers the best connection.
Whys is it recommended to use SonosNet and not google wifi? Do you have to manually switch between networks (google wifi and sonosnet) on you mobile phone to manage the Sonos units (when they are on their own sonosnet network)?
For a Sonos system in WiFi ('Standard' mode) meshed WiFi systems can introduce potential problems. That's why Sonos typically recommend wiring a Sonos component -- to a LAN port on one of the meshed pods -- which puts the system into SonosNet mode.
You'd just use your phone as normal. The SonosNet mesh and WiFi mesh will be bridged together by the wired Sonos device. If your phone is an Android, Sonos also offers the option to attach it directly to SonosNet, using the players as access points. This is a bonus, not mandatory.