I don’t have a good solution to this case yet I am afraid. We started out with just monthly targets to keep it simple well aware that in many cases, that is too limited - holidays being the most obvious one.
Once we are a bank, it could be interesting maybe to combine budgeting with savings pots. So if you e.g. have a bill of £150 to pay every quarter, you set a budget of £50 per month. In months where you do not pay, the money are set aside so that you won’t see a spike in your spending when you actually have to pay the bill.