Securing Firebase with SMS verification or Email help needed

Right now the entire database is public, someone expert could just hack the app and do whatever he wants with the data

https://docs.thunkable.com/realtime-db

If you are concerned about the safety of your database, you can edit database rules on reading and writing data.

I already read that but I’d like to understand deeper firebase security rules and if I can set up SMS OTP

I can help.

Really? that would be great