Yes to the last bit of edit.

No, because federated.

You don’t need same app on both for phone to use matrix, there are multiple apps that can communicate over matrix, some may not be available on both iOS and Android.

But if you were to use matrix, I’d recommend using Element which just happens to be available on iOS and Android.

Linux just gave me the foundation…

same… seems to work for me as well, i assume infinity dev hasnt revoked the api yet, not sure why, if thats the case, he will get billed.