How can I get user displaynames who posted comments with Firestore v9 in React

firebase.js

import { initializeApp } from 'firebase/app';
import { getFirestore } from "firebase/firestore";

// TODO: Replace the following with your app's Firebase project configuration
const firebaseConfig = {
    apiKey: "",
    authDomain: "",
    projectId: "",
    databaseUrl: "",
    storageBucket: "",
    messagingSenderId: "",
    appId: "",
    measurementId: ""
};

const app = initializeApp(firebaseConfig);


export const db = getFirestore(app);

user.js

import { db } from "./firebase";
import { collection, addDoc, getDocs } from "firebase/firestore";
export const getuser = async () => {
    try {
        const querySnapshot = await getDocs(collection(db, "user"))
        return querySnapshot
    }
    catch (e) {
        console.error("Error adding document: ", e);

    }
}

import React, { useEffect, useState } from 'react'
import { getuser } from './user.js'
export default function Home() {
    const [user, setUser] = useState([])
    useEffect(() => {
        let data = await getuser()
        let users = []
        data.forEach(doc => {
            users.push(doc.data())
        })
        setUser(users)
    }, []);
    return (
     <div>
      {user.map((item, index) => (
          <div>
          <p>{item.displayName}</p>
          <p>{item.idea}</p>
          </div>
       ))}
      </div>)
}