Look - this forum is filled with the same issue - if you have a household full of Google devices, the setup is massively broken. Why? Well from what I can tell they tried to make the setup easy by sharing wifi information between devices via Bluetooth during setup. The problem is that the "assisting device" is usually the first device you set up and it ends up being too far away (or through too many walls) to support setup of the other devices. This makes it almost impossible to setup a home with multiple google home devices.
The way to fix this is to delete all your devices and attempt to start with a centrally located device, then grow the device list from there. This sort of works - but takes a lot of experimentation to get right. Google could solve this whole issue with a really simple software update that joins you to the device wifi network, has you enter your wifi password, and then rejoins that device to your household. Seriously google - are you listening? IF the auto-join fails, default to wifi setup. I am over 2K$ invested in google devices that barely work, sometimes fall off the network, and are impossible to add.
