Twitter Login with flutter and firebase not working 100%

Question

I wanted to implement twitter login into my app... so far so good I got it to run but now Im kinda stuck and I don't know whats going on... I wrote a function (see below) that lets you sign in with the apikey and so on but when I click the button I get redirected to the twitter API but there is no new user on firebase... I don't know why this is happening... see the code below: (for "example" in the API keys I inserted my API keys I just didn't want to publish them here...)

Furthermore when I dismiss the Google Sign In dialog on my iPhone 13 emulator I get an Error (PlatformException) although I use a try-catch block... On my physical android device it worked properly... idk why this is happening...

import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:google_sign_in/google_sign_in.dart';
import 'package:twitter_login/twitter_login.dart';
import 'package:wineapp/constants.dart';

class AuthService {
  FirebaseAuth firebaseAuth = FirebaseAuth.instance;

  //Register User

  Future<User?> emailRegister(
      String email, String password, BuildContext context) async {
    try {
      UserCredential userCredential =
          await firebaseAuth.createUserWithEmailAndPassword(
        email: email,
        password: password,
      );
      return userCredential.user;
    } on FirebaseAuthException catch (e) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(
            e.message.toString(),
            style: GoogleFonts.poppins(
              textStyle: const TextStyle(
                color: mainTextColor,
                fontSize: 12,
                fontWeight: FontWeight.w600,
              ),
            ),
          ),
          backgroundColor: primaryColor,
        ),
      );
    } catch (e) {
      print(e);
    }
  }

  //User login
  Future<User?> emailLogin(
      String email, String password, BuildContext context) async {
    try {
      UserCredential userCredential =
          await firebaseAuth.signInWithEmailAndPassword(
        email: email,
        password: password,
      );
      return userCredential.user;
    } on FirebaseAuthException catch (e) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(
            e.message.toString(),
            style: GoogleFonts.poppins(
              textStyle: const TextStyle(
                color: mainTextColor,
                fontSize: 12,
                fontWeight: FontWeight.w600,
              ),
            ),
          ),
          backgroundColor: primaryColor,
        ),
      );
    }
  }

  //User SignIn with Google
  Future<User?> signInWithGoogle() async {
    try {
      //Triger the authentication flow
      final GoogleSignInAccount? googleUser = await GoogleSignIn().signIn();
      if (googleUser != null) {
        //Obtain the auth details from the request
        final GoogleSignInAuthentication googleAuth =
            await googleUser.authentication;
        //Create a new credential
        final credential = GoogleAuthProvider.credential(
          accessToken: googleAuth.accessToken,
          idToken: googleAuth.idToken,
        );
        //Once signed in, return the UserCredential
        UserCredential userCredential =
            await firebaseAuth.signInWithCredential(credential);
        return userCredential.user;
      }
    } on FirebaseAuthException catch (e) {
      print(
        e.toString(),
      );
    }
    return null;
  }

  //Sign Out function
  Future googleSignOut() async {
    await GoogleSignIn().signOut();
    await firebaseAuth.signOut();
  }

      void twitterLogin() async {
    // Create a TwitterLogin instance
    final twitterLogin = TwitterLogin(
        apiKey: 'example',
        apiSecretKey: 'example',
        redirectURI: 'flutter-twitter-login://');

    // Trigger the sign-in flow
    await twitterLogin.login().then((value) async {
      if (value.authToken != null || value.authTokenSecret != null) {
        final twitterAuthCredential = TwitterAuthProvider.credential(
          accessToken: value.authToken,
          secret: value.authTokenSecret,
        );

        await FirebaseAuth.instance.signInWithCredential(twitterAuthCredential);
      }
    });
  }
}

Thanks for your help in advance:)