> As such I have a very hard time believing that Librem with be as secure as modern Android.
Android isn't secure, it's limited, that's the whole problem here. Any security you can't control isn't a security feature but just a limitation. It's "secure" because you can't do anything interesting with it.
Using Android with reluntance, since my favourite OSes were Symbian and Windows Phone, additionally I dislike Android J++ and the NDK is relatively constrained.
Still, I can do plenty of interesting things with my Android gadgets.