I have the Sonos app downloaded on my iPad as well on my google pixel 7 pro softphone.
Did you setup one Sonos and then use the Controller to add the other Sonos to that one? If not you may have created two households.
Try factory resetting the lone One and then making sure you are connected to the others, then do the add process.
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.