Two quick things. First, I don’t think Sonos ‘supports’ WiFi 7, and honestly, I wasn’t aware the consortium had yet agreed on what features are WiFi 7 yet. On the other hand, I was under the impression that WiFi 7 was backwards compatible with earlier versions of networking.

Sonos doesn’t make a router, so I’m a bit concerned about your statement that you’re running a Sonos Router AX6600 - WIFI 7.

I’d try a couple of things. First, in whichever router this is, try turning off WiFi 7, and see if that helps things. Second, I’d try a call to 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.

I just upgraded to Unifi Wi-Fi 7 about two weeks ago, absolutely no issues with a Beam (gen 1), One’s (gen 1), Era 100 ‘s and Era 300’s. 
 

If you have not done so, a power off for a few minutes is a must, but as Bruce says… contact support directly.

I searched for, but can’t find the router model that you have quoted.

As a quickie test make sure that you have correctly entered the WiFi username and password, power down all of the SONOS units, and keep the BOOST’s powered down. You may need to, at least temporarily, wire another SONOS unit to the network. BOOST’s are using very old, essentially obsolete, technology.

There is a recent thread somewhere about recent ASUS Wifi 7 routers having trouble with Sonos, due to an unusual default choice of security modes. Is AX6600 an ASUS model?