And that organization - the IRS - won’t tell you the information they have. They want you to guess and tell them what you have, so they can tell you if you got it right or not.
This really needs to be fixed.
In Australia, the stuff the government knows about you gets prefilled in the tax return form. Not as good as other countries where the entire thing is completed for you, but better than the USA. The form is significantly shorter than the US one.