Does Google Android work on the FP4

[yvmuell]

You mean if you can switch from e/OS to the Fairphone OS? Its all Google Android as Android is from Google

And overall this is still true as you are in the US

My Fairphone App: Your digital sustainability tool

You can install all OS versions mentioned at oslist . But, as mentioned here I suppose that VoLTE and VoWiFi might no longer work then. And after installing another OS be aware that relocking the bootloader can be dangerous.