I tried the example (Xamarin.Forms - Accessibility) app out of interest.
If I compel it for Android the accessibility seems to work.
If I compile the same code, without any changes, for iOS VoiceOver only announces AutomationProperties values to e.g. "Instructions Label" the text on the screen "Accessibility Demo".
This behaviour makes no sense to me, as a screen reader user.
Have I missed something?
PS. The system does not let me post my questions with a link to the example in it. Sorry about that. You shout be able to finde the example by copy Xamarin.Forms - Accessibility in to google.