You're addressing a lot more than I even attempted to address.

I was really just pointing out that devices like this:

https://www.hmd.com/en_us/nokia-2780-flip?sku=16WNDL11A01

and services like e.g. SMS text reminders from Internet services do no run on Android. The green is not a signifier of Android, just of non-encrypted. Or non-Apple, if you want to be less precise. (Apple devices where encryption is disabled also appear as green.)