Firebase analytics data not accurate

Question

We just deploy our web gaming platform and starts ads in Facebook and Google. Per day facebook send us 10k users. We use a tool call mouseflow to check user behaviours and we have around 9k users.

But Google analytics visitors is 116. We don't really what to do.

Our configuration is simple. We just copied and past the conf google provided in our

// Import the functions you need from the SDKs you need
import { initializeApp } from "firebase/app";
import { getAnalytics } from "firebase/analytics";
// TODO: Add SDKs for Firebase products that you want to use
// https://firebase.google.com/docs/web/setup#available-libraries

// Your web app's Firebase configuration
// For Firebase JS SDK v7.20.0 and later, measurementId is optional
const firebaseConfig = {
  apiKey: "XXXXXXXXXXXXXXXXXXXXXXXX",
  authDomain: "XXXXXXXXXXXXXXXXXX",
  projectId: "XXXXXXXXXXXXXXXX",
  storageBucket: "XXXXXXXXXXXXXXXXXX",
  messagingSenderId: "XXXXXXXXXXXXXXXXXXXXXXX",
  appId: "XXXXXXXXXXXXXX",
  measurementId: "G-25L48DR5H1"
};

// Initialize Firebase
const app = initializeApp(firebaseConfig);
const analytics = getAnalytics(app);

and in main.ts

/* initialize firebase */
initializeApp(firebaseConfig);

What are we doing wrong ?