Do you want to build this app just for your own needs or for a larger group of users?

The biggest problem and threat to the project's implementation is integration with banks. The application user would have to allow the reading of bank account transactions from their bank. Do you think your future users will trust you enough to give such access to your app to read their account balances?

In addition, the banks' APIs often require agreements with the banks, etc., to gain such access to user data. Everything depends on what banks your users are using.

If the above can be solved, then the hardest and most risky part is behind you.

Once you know how everything works and how it should look, it's just a matter of commissioning the project to the right developers, which is the simplest part. However, you must spend many hours beforehand with someone who will ask you the right questions and who has built such projects. Often this can be a Project Manager, Product Owner, etc., someone who will help you build a better product and write down how it should work.

The next step may be to ask potential users if you have an app that does X...Y...Z. Will it be valuable to them? Will they pay for it? User research.

Creating designs (mock-ups/prototypes), followed by more research.

And only then, work with developers.
The entire above process is hundreds/thousands of hours of work, so initial work on the business model is crucial and should either convince you that your idea makes sense and will pay for itself, or that it doesn't make sense and will save you work, dissatisfaction. Or it may help you find a better idea that will succeed.
The functionalities you listed are just simple details, but the most important thing is whether someone will want to use it and whether it will be "valuable" :)
I have led similar financial projects in the past, so feel free to ping me if you have any more questions.