Как получить данные и отобразить их в recyclerview в фрагменте с viewmodel

Не могу получить данные и отобразить их в recyclerview в фрагменте с viewmodel (java).

ScoreboardFragment.java

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProvider;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.aad.ScoreboardAdapter;
import com.aad.User;
import com.aad.databinding.FragmentScoreboardBinding;

import java.util.ArrayList;
import java.util.Map;

public class ScoreboardFragment extends Fragment {

    private FragmentScoreboardBinding binding;
    private ScoreboardAdapter scoreboardAdapter;
    private ArrayList<User> users;
    private ScoreboardViewModel scoreboardViewModel;

    public View onCreateView(@NonNull LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {
        scoreboardViewModel =
                new ViewModelProvider(this).get(ScoreboardViewModel.class);

        binding = FragmentScoreboardBinding.inflate(inflater, container, false);

        scoreboardViewModel.getUsers().observe(getViewLifecycleOwner(), new Observer<ArrayList<User>>() {
            @Override
            public void onChanged(ArrayList<User> users) {

                updateDataFromViewModel();

            }
        });

        updateDataFromViewModel();

        View root = binding.getRoot();
        return root;
    }

    private void updateDataFromViewModel() {

        users = scoreboardViewModel.getUsers().getValue();

        binding.rv.setHasFixedSize(false);

        binding.rv.setLayoutManager(new LinearLayoutManager(getContext()));
        scoreboardAdapter = new ScoreboardAdapter(getContext(), users);
        binding.rv.setAdapter(scoreboardAdapter);

    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        binding = null;
    }
}

ScoreboardViewModel.java

import android.util.Log;

import androidx.annotation.NonNull;
import androidx.lifecycle.LiveData;
import androidx.lifecycle.MutableLiveData;
import androidx.lifecycle.ViewModel;

import com.aad.User;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

import java.util.ArrayList;

public class ScoreboardViewModel extends ViewModel {

    private final MutableLiveData<ArrayList<User>> users = new MutableLiveData<>();
    private ArrayList<User> u = new ArrayList<>();

    public ScoreboardViewModel() {

        getData();

        users.setValue(u);

    }

     private void getData(){

         FirebaseDatabase.getInstance()
                 .getReference("user/")
                 .get().addOnSuccessListener(new OnSuccessListener<DataSnapshot>() {
             @Override
             public void onSuccess(DataSnapshot dataSnapshot) {
                 for(DataSnapshot ds : dataSnapshot.getChildren())

                     u.add(ds.getValue(User.class));
                 Log.d("FACT", u.get(0).getEmail());
             }
         });

         FirebaseDatabase.getInstance()
                 .getReference("user/")
                 .addListenerForSingleValueEvent(new ValueEventListener() {
                     @Override
                     public void onDataChange(@NonNull DataSnapshot snapshot) {

                         for(DataSnapshot ds : snapshot.getChildren())

                             u.add(ds.getValue(User.class));

                     }

                     @Override
                     public void onCancelled(@NonNull DatabaseError error) {

                     }
                 });

    }

    public LiveData<ArrayList<User>> getUsers() {
        return users;
    }
}

ScoreboardAdapter.java

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

public class ScoreboardAdapter extends RecyclerView.Adapter<ScoreboardAdapter.ScoreboardViewHolder> {

    private ArrayList<User> users = new ArrayList<>();
    private Context context;

    public ScoreboardAdapter(Context context, ArrayList<User> expenses) {
        this.users = expenses;
        this.context = context;
    }


    @NonNull
    @Override
    public ScoreboardViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(context).inflate(R.layout.score_row, parent, false);

        return new ScoreboardViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ScoreboardViewHolder holder, int position) {

        holder.name.setText(users.get(position).getUsername());
        holder.points.setText(users.get(position).getPoints());

    }

    @Override
    public int getItemCount() {
        return users.size();
    }

    public static class ScoreboardViewHolder extends RecyclerView.ViewHolder {

        private TextView name, points;

        public ScoreboardViewHolder(@NonNull View itemView) {
            super(itemView);

            name = itemView.findViewById(R.id.username);
            points = itemView.findViewById(R.id.points);


        }

    }

}

score_row.xml

<?xml version="1.0" encoding="utf-8"?>
<com.google.android.material.card.MaterialCardView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="8dp"
    style="@style/Widget.Material3.CardView.Elevated"
    app:cardCornerRadius="30dp">


    <LinearLayout
        android:layout_width="match_parent"
        android:orientation="vertical"
        android:layout_height="match_parent">

        <TextView
            android:id="@+id/username"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textSize="20dp"
            android:layout_margin="15dp"
            android:textStyle="bold"
            android:text="username"/>

        <TextView
            android:id="@+id/points"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginHorizontal="15dp"
            android:layout_marginBottom="15dp"
            android:textSize="18dp"
            android:text="points"/>

    </LinearLayout>

</com.google.android.material.card.MaterialCardView>

fragment_scoreboard.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ui.scoreboard.ScoreboardFragment">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv"
        android:layout_margin="15dp"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</androidx.constraintlayout.widget.ConstraintLayout>