the problem with Android fragmentation is as old as Android. If you're a journalist, activist or anyone who needs critical security on a phone you're better off not having one.
The options for anyone else is usually a) always use the latest iOS device or b) use a hardened Android, or c) use a dumb phone for all non-critical comms. I should repeat that: if you're worried about security consider using f2f interaction because the number of places you're likely to trip up are endless no matter what device.