I am building an app related to online bookings of Barbers in my city.I am planning to use Firebase to store my data and showing realtime updates. What will be the right option i.e. Realtime Database or Firestore. As much as I read, Firestore is great but it costs the developers according to number of queries and in my case query numbers will be much higher as I am planning to show realtime update to clients for their booking status. And I am a naive in this area so suggest which one will be easy to learn.