If the new router is using your original WiFi credentials, or it has Airtime Fairness or QoS enabled, then disable those two features and also ensure the 2.4Ghz WiFi radio is set to 802.11b/g/n compatible and try it with security mode WPA2 AES and see if that resolves the connection issue.

If no luck with the above, and/or the router is using different WiFi credentials, then try wiring one Sonos device to the router, so that the system uses the internal SonosNet signal instead and reboot your speakers - then try adding the new WiFi credentials to the Sonos setup by going to ‘Settings/System/Network/Manage Networks’ in the Sonos App and select ‘update networks’ to add your new WiFi credentials to all your sonos devices.

Afterwards, try uncabling the one wired device and see if all will then run on your routers WiFi signal.