Honestly I would take it back and get another brand, had this product for many years and love the sound but the app is making these speakers useless and keeps getting worse...If they were not so expensive they would be in the trash at this point!

Return the system.. Sonos is not what it was . It’s turned into crap.

You may be able to get it to work with help from others on this forum.  Or you may not.  "Devices not showing up” is a common problem with the new app.  Forget calling customer support. They are overwhelmed.   Return it unless you enjoy spending hours tinkering with problematic technology with no guarantee of success. You can always revisit in the fall.

If you ARE up with tinkering, you could try turning off your router and the Sonos system and closing the app.  Turn on the router and wait a few minutes until it is fully connected to the internet.  Then open the sonos app.  Then turn on each device.  See if everything connects.

If that doesn’t work,  assign a reserved IP address for each Sonos device.  You do so in your router.  Then repeat the process outlined above.