ebbe,

The TP-Link Deco M9 Plus System is not entirely all that 'friendly, in that each hub selects its own WiFi channels automatically, with no option to fix them to a specific channel. In the discussion link below, taken from the TP-Link community, there is ‘hope’ that the developers at TP-Link will one day rectify the issue and allow a user to fix the Wifi channel(s) for each hub. The Hubs clearly are not doing what they should be doing and interference is an issue apparently. See here...

https://community.tp-link.com/en/home/forum/topic/154561?page=1

With those things in mind, Sonos devices and their mobile controllers, really need to all operate on the same WiFi channel to communicate with each other successfully and therefore with this type of Wifi mesh system, they ideally need to run on their own internal SonosNet wireless signal, which means one device needs to be wired to the main TP-Link Deco Hub.

SonosNet is able to run on three primary non-overlapping WiFi channels, which are 1, 6 or 11. 

So if you can get your TP-Link Hubs to all avoid one of those SonosNet channels, then the Sonos system should operate fine in wired SonosNet mode. What no-one can guarantee however, is that your TP-Link Hubs over-time, may decide to automatically jump onto the chosen SonosNet channel and start to interfere with the communication between Sonos devices.

As the TP-Link community users mention, everyone can only hope that the TP-Link developers provide their uses with the tools to make their WiFi channels static.

I also understand that the same situation may apply to the Google WiFi Mesh System and many users with that type of network setup have successfully managed to run their Sonos devices, in wired SonosNet mode, with those hubs dotted about their home.

Hope that assists.

THANKS, I will try to set it up, and hope TP-Link will support fix channels in their sw.

// Ebbe