Hard to tell from your description, but it seems like a potential WiFi interference situation. I’d start with a network refresh, by unplugging all Sonos devices from power, them, while they’re unplugged, reboot your router. Wait two minutes, then plug back in your Sonos. Your original post suggests you’ve done both, just not at the same time / in sequence, which likely, as you’ve found out, doesn’t help much. After the Sonos devices have rebooted and reconnected, check in your controller for any possible updates to both the speakers and the controller, and apply them. Thankfully, that’s a one process thing that handles both. Once that is applied, check your Sonos again, to see if things are taken care of.
If not, I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. Don’t post the resulting diagnostic number here, their lawyers get sensitive about GDPR.
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.
Somtimes you can find and work around wifi issues.
https://support.sonos.com/en-us/article/improve-your-sonos-products-wifi-connection
Are any of your Sonos connected to Ethernet? Sometimes a wifi only configuration works best.
