I've submitted a diagnostic 312655413.
Best answer by jnak
Then I noticed that voice services in the Sonos app was unavailable and would give me the same "not connected to internet issue". I checked the Account in the Sonos app, and it was somebody else's email address! I assume it came from the Play:5, since it's the only thing that changed, but it was brand-new, in the box. I couldn't transfer ownership either. I deleted the app from my phone, reinstalled, re-signed in, and now everything is fixed. I was able to change the line-out on the Connect to fixed and can see the voice services again.
I'm bewildered as to how this happened, but it's fixed now.