Ignore the reference to 2019 in the drop-down text for code P in 2020 TurboTax. The drop-down text assumes that you are entering a 2020 Form 1099-R, not a 2021 Form 1099-R. Code P actually means taxable on the tax return for the year prior to the year of the Form 1099-R, but that's too much for the developers to put in the drop-down text. Just select code P and later answer that it's actually a 2021 Form 1099-R.