What is the best way to connect my application to backend server
I'm new to Android app development and currently working on my new app upto now I used firestore to load all the data for my app like products list and to save user details their order details and lots other stuff. Firestore made things made but it is not that effective for me. And I worry that could it manage a lot of user base and even I have some concerns about that. Now I really want to use a backend database for the app and connect it with my app. So that I can control everything from the server database. My app helps users to find local services like appliances repairs and other so the products in my app needs to updated real-time and I collect user basic information and I have to link user orders to each of them. And additional orders page to list all orders from all users. Suggest me a proper way of how can I achieve that what do I have to do what should I learn which libraries I have to use to connect the dots to make a complete professional app.