How to handle deeplinks in react

Question

I am trying to implement deeplinks in my app using firestore's dynamic links. When the app is opened using a deeplink, I want to show a modal to the user. I am new to react and I am not sure how to implement this. When the app is opened using the dynamic link, I can get the link in App.js

useEffect(() => {
    const unsubscribe = dynamicLinks().onLink(handleDynamicLink);
    return () => unsubscribe();
  }, []);

  const handleDynamicLink = link => {
      //Show Modal
  };

 return (
    <RootStoreProvider value={rootStore}>
      <SafeAreaProvider initialSafeAreaInsets={initialWindowSafeAreaInsets}>
        <IconRegistry icons={EvaIconsPack} />
        <ThemeContext.Provider value={{ theme, toggleTheme }}>
        <ApplicationProvider {...eva} theme={eva[theme]}>
          {!rootStore.authStore.isLoggedIn && !startedPressed ?  <WelcomeSliderScreen pressed={getStartedPressed}></WelcomeSliderScreen> :
          <RootNavigator
            ref={navigationRef}
            initialState={initialNavigationState}
            onStateChange={onNavigationStateChange}
          />
          }
        </ApplicationProvider>
        </ThemeContext.Provider>
      </SafeAreaProvider>
    </RootStoreProvider>
  )
}

What is the best way to implement this logic? I started to implement a deepLinkStore but now a start the think that this is not the best solution

const handleDynamicLink = link => {
       rootStore && rootStore.linkStore.setDeepLink(link);
  };

The problem is that rootStore is sometimes null there, I don't understand why. Shall I just provide a parameter in RootNavigator? Something like this

const [deepLink, setDeepLink] = React.useState(null)

const handleDynamicLink = (link) => {
setDeepLink(link);
}
         <RootNavigator
            ref={navigationRef}
            initialState={initialNavigationState}
            onStateChange={onNavigationStateChange}
            deepLink={deepLink}
          />

Is this the way to go? How can I access the deepLink parameter in a functional component?