Our solutions are based on Firebase.
The complete solution uses the following from Firebase:
1. Firebase Realtime Database - It is fully hosted by Google as it is Google's product.
2. Firebase Cloud Functions - For Server side APIs designed specifically for Firebase database events and Firebase database.
3. Firebase Authentication - Full authentication is integrated with Firebase for Email, Phone OTP, and Social Logins.
4. CronJob Scheduler - Uses Firebase's inbuilt scheduler system.
5. Push Notification Service - FCM is used which is Google's full service for handling push notifications.
6. Hosting. - The react webpages easily get hosted on Firebase Hosting.
Out of all the above, you can only host the WebPages to another hosting.
But for the rest of points 1 to 5 will still require Firebase services only.
And Firebase autoscale based on your load and has usage-based pricing -