justifyContent was given a value of middle, this has no effect on headerStyle.
//Its defaulted to center for iOS and left for Android device
<NavigationContainer>
<NavStack.Navigator initialRouteName='Contacts'>
<NavStack.Screen
name='Contacts'
component={ContactsScreen}
options={({ navigation }) => ({
title: "My Contacts",
headerTitleAlign: "center",
})}
/>
<NavStack.Screen
name='AddContact'
component={ContactAddScreen}
options={{ title: "Add Contact" }}
/>
</NavStack.Navigator>
</NavigationContainer>