This is usually an STP issue. Especially, if the system or a network switch has been newly installed. If a component does not handle STP properly, there will be a “network storm”, and throughput will stall. This will strike when multiple Sonos components are wired to the network. On must replace or reconfigure the bad actor. One strategy to stop the storm is to wire all of the Sonos units through a single Sonos unit. This will allow Sonos to manage its STP. Note that Sonos ports are 10/100.

I have spoken to Sonos tech support at length about this issue previously, this is going back a few years but they advise not to connect your Sonos system to multi access point wifi systems, as the Sonos devices can not differentiate between the differnt access points and it causes issues. Ive seen this happen with other smart home products in the past where multi access point wifi installs have been done, most recently i saw this on a Pyronix Alarm system.

Sonos tech's solution is to have one Sonos device hard wired to the network and the rest of the devices meshing together through the SonosNet not using the wifi. If you dont have a LAN cable by any of the Sonos locations, you can use a boost instead by your router, to be the wired Sonos device.

Access points using multiple channels is not a great idea for Sonos in WiFi mode. I only have one installation in WiFi mode and there is a single access point. This installation works fine.