react-navigation BottomTabNavigator VERY slow on some Android devices - performance

Question

I've got a minimal test ReactNative test in Expo running. 2 screens, both just have Text within a View.
This is run on a MBP, and tested on my Android device (Note10+) via QR code.
It is not just slow, it's unresponsive most of the time, when it does navigate to a tab on click then it's either instant (rarely) or takes 5-10 seconds. But usually nothing happens.
There are no errors being shown, replacing the same code with a Stack or Drawer works fine.
2 basic screens:
function StackScreenA0({navigation}) {
return (
<View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
<Text>Test stack 0</Text>
<Button title="goto 1" onPress={() => navigation.navigate('Screen A1')} />
</View>
);
}
function StackScreenA1({navigation}) {
return (
<View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
<Text>Test stack 0</Text>
<Button title="goto 0" onPress={() => navigation.navigate('Screen A0')} />
</View>
);
}
App code (minus imports):
const Tab = createBottomTabNavigator();
function App() {
return (
<NavigationContainer>
<Tab.Navigator initialRoutName='Screen A0'>
<Tab.Screen name="Screen A0" component={StackScreenA0} />
<Tab.Screen name="Screen A1" component={StackScreenA1} />
</Tab.Navigator>
</NavigationContainer>
);
}
export default App;
I've never used Expo before but I can't imagine this is normal behaviour but cannot see a reason for it working so badly.
EDIT: I've found other devices to test and tabs are fine on iPad4, Galaxy9, but seriously bad on Note10+.
Rich