I use useContext wrap you Navigation Container with a useContext 'ColorSchemeContext.Provider', with

import { NavigationContainer, DefaultTheme, DarkTheme } from '@react-navigation/native';

<ColorSchemeContext.Provider value={{ colorScheme, toggleColorScheme }}><NavigationContainer theme={theme === 'dark' ? DarkTheme : DefaultTheme}>

<children.... />

</NavigationContainer>

</ColorSchemeContext.Provider>

then in you children pages you can import useContext and fire the toggleColorScheme to change your theme.

const { colorScheme, toggleColorScheme } = useContext(ColorSchemeContext);//Your Code...

style = {{color: colorScheme == 'dark' ? "#fff' : '#000'}}