How to send links properly from an emulator for custom passwordless email user experience

[psdewar]

I am using the following latest versions to leverage react-navigation's NavigationContainer linking prop in order to receive a link from a user's email whether or not they are new.

• @react-native-firebase/auth (v14)
• @react-native-firebase/dynamic-links (v14)
• @react-navigation/native (v6)

My understanding is that admin auth's generateSignInWithEmailLink, which I attempt to use in a cloud function, replaces auth's sendSignInLinkToEmail to customize the sign in email via, for example, SendGrid. isSignInWithEmailLink always returns true from the app when I click a link generated from sendSignInLinkToEmail. Even though I get a link from generateSignInWithEmailLink, I am not able to redirect correctly to the app as seen in the image below, even when all emulators are ready from the terminal.

I have read most of the docs on Firebase Dynamic Links and spent a week trying to piece together a solution for react-native. localhost and demodev.page.link subdomain are already an authorized in Firebase and I pass the same email and ActionCodeSettings to both functions.

  const actionCodeSettings: ActionCodeSettings = {
    handleCodeInApp: true,
    url: `https://demo-dev.app/new?email=${email}`,
    iOS: {bundleId},
    android: {packageName: bundleId, installApp: true},
    dynamicLinkDomain: `${
      PROJECT_ID === 'demo-dev' ? 'demodev' : 'demo'
    }.page.link`,
  };

At first glance, my configuration is wrong somewhere. Any tips? Additionally, how do I prevent the email itself from getting stamped as a possible phishing scam that's automatically sent to junk email?