You could be experiencing wifi interference, certainly. Worth reading that FAQ and applying the fixes that may apply in your situation.
If it’s duplicate IP addresses that is your issue, you’re unlikely to have caught it by shutting off the entire house. You’d need to power down all Sonos devices and reboot the router while they are powered down. Doing both at the same time may, depending on boot speed for each device, end up with the same duplicate IPs as before.
If neither of those work out, I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, 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 phone folks, they have tools at their disposal that will allow them to give you advice specific to your Sonos system and network.