Using gov one is definitely not recommended, first point of contact should always be another form first. not to mention they are just not gonna be flexible.

I track my asset, income, fixed cost (eg insurance, transport) in an offline excel and one other app for stock.

I try to cross check the spending every few months going through every single transaction in statement to get an overview.

That being said there's a lot of banking app that use API to help categorising spending, I just prefer doing it myself to make sure the breakdown is correct