To complete your app development and deploy it to Google Play and App Store, you need more additional changes. Please follow guides bellow for more details.
Change App Icons
Add App Icons and Launch Screens to React Native Apps (iOS & Android) guide by Scott Stewart on medium.com
Running on Device
Running On Device guide from React Native
Publishing to Google Play Store
https://reactnative.dev/docs/signed-apk-android
13 steps to Deploying React-Native Android App to Google Play Store using Android Studio guide by Jolanta on medium.com
Publishing to App Store
How to Deploy a React Native IOS app on the App Store guide on readybytes.in