I have just 25 records, it takes some time to load
I have also added counter with where clicking + button will increment and - will decrement, for that as well it loads a spinner as soon as the button is clicked and then updates the number
Will it be the same even when the app is published as Android/iOS?
I would say that’s about normal.
The app / lists load quickly. The slow part is your +/- buttons.
Try updating the number to an input box, then having the user submit that value to the database on a submit button click.
At the moment you are updating the database on each +/- action.
At the moment I’ve got good performance on iOS and terribly slow, unusable on Android (I am trouble shooting this and will share what I find).