When to merge features into a "master" mobile app or create a dedicated mobile app

The general question is how do you decide that these features should be merged to an existing mobile app OR we should build a dedicated mobile app?

Let's say for instance that you work for a bank.

From the user perspective, you've identified two goals/tasks: 1. I want to see how much money is on my account. 2. I want to transfer money to some other bank account. If you were to do more research, I guess you'd find more goals/tasks (all that is only an example).

From the bank perspective, they started with one app "Name Of The Bank." And then at some point, it became messy because the objective of the app became unclear, the users' profiles (personas) and activities also became unclear.

So how do you choose when it would make more sense to split and create a new product or when it's ok to add on?

Thanks for your feedback, experience tips, readings, etc.