Is anything in here of use to you?

https://support.sonos.com/en-us/article/switch-sonos-between-a-wireless-and-wired-setup

Or in this:

https://support.sonos.com/en-us/article/connect-sonos-to-a-new-router-or-wi-fi-network

If neither of the above posts help, and the PLAY:3 is set up and working while wired, but not wirelessly, there is a small possibility that the WiFi antenna in it has gone bad. The only ‘certain’ way to tell, is to submit a system diagnostic while it is wired and showing up, and call Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

Trying to keep things easier here - maybe approach this issue from a different angle and change your new router WiFi settings instead to broadcast/use the same SSID/Password credentials as your previous router - your Sonos devices should then auto-connect to the WiFi network and all should again work over WiFi.