I would call Sonos Support directly to discuss it.

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

Are you able to temporarily connect a Sonos speaker to your network with an Ethernet cable? This may help you get your speakers setup and updated.

Then go to Settings-Network-Manage Network-Update network and input your WIFI settings. You can remove the cable once this is done.