Just reading that gave me a headache. In Latvia, heres how the system works.

If you have no deductible spending (medical, education, donations).:

• Log into the govt system.
• Press a button to generate tax form.
• Press verify and submit.
• Pay what you owe or wait for the tax return.

If you have deductible info

• As before but also scan your receipts, and add the info on each receipt to the form. Can done easily via an app, which handily (sometimes correctly) can autofill the needed info. You can do this at any point in time, so you can do it whenever you get a deductible receipt.