if somebody is facing the same issue with firabase emulator for an expo app running on ios simulator, I got it fixed with below steps.

add host to the firebase.json in firebase side

"emulators": {
    "functions": {
      "port": 5001,
      "host": "0.0.0.0"
    },
    "firestore": {
      "port": 8080,
      "host": "0.0.0.0"
    },
    "ui": {
      "enabled": true
    },
    "singleProjectMode": true,
    "export": {
      "path": "emulator-data"
    }
  }

and then in expo side, where you initialize firebase apps

import Constants from "expo-constants";
import { getApps, initializeApp } from "firebase/app";
import { getAuth } from "firebase/auth";
import { connectFirestoreEmulator, getFirestore } from "firebase/firestore";
import { connectFunctionsEmulator, getFunctions } from "firebase/functions";

const firebaseConfig = {
  apiKey: process.env.EXPO_PUBLIC_FIREBASE_API_KEY,
  authDomain: process.env.EXPO_PUBLIC_FIREBASE_AUTH_DOMAIN,
  projectId: process.env.EXPO_PUBLIC_FIREBASE_PROJECT_ID,
  storageBucket: process.env.EXPO_PUBLIC_FIREBASE_STORAGE_BUCKET,
  messagingSenderId: process.env.EXPO_PUBLIC_FIREBASE_MESSAGING_SENDER_ID,
  appId: process.env.EXPO_PUBLIC_FIREBASE_APP_ID,
};

const app = getApps().length ? getApps()[0] : initializeApp(firebaseConfig);
const origin = Constants.expoConfig?.hostUri?.split(':')[0] || 'localhost';

export const db = getFirestore(app);
export const auth = getAuth(app);
export const functions = getFunctions(app, "asia-south1");

if (__DEV__ && process.env.EXPO_PUBLIC_USE_EMULATORS === "1") {
  console.log(`🔌 Using local Firebase emulators... ${origin}`);
  connectFunctionsEmulator(functions, origin, 5001);
  connectFirestoreEmulator(db, origin, 8080);
}

export default app;