We have seen a common issue related to Sonos speakers and Mesh networks. Not just TP-Link Mesh like Deco or OneMesh but in general. In doing some research on Sonos website and community, we found that this is a known concern. What we found is the following:
On Sonos system requirements page it states on a foot note that: “In WiFi mesh networks, Sonos products must be wired to the primary mesh node if using a wired setup”
So, if you are having connection issues, please try to setup your Sonos speakers this way. Also, another option that was posted on a community thread is using their Sonos Boost device. From what we can gather this device is a WiFi extender specially for the Sonos speaker system. We cannot state if this option will work or not, but the Sonos community has it marked as an Answer on the thread.
Please know that TP-Link cannot endorse any of these solutions and do recommend you still reach out to Sonos for any support beyond these suggestions.
*Screenshots provided as we are unable to link 3rd party sites