In 2020 TurboTax, when you enter the 2021 Form 1099-R you must, when asked, indicate that the form is a 2021 form. This will cause TurboTax to treat the box 2a amount as taxable on the 2020 tax return and will not tell you that it should be reported on your 2019 tax return. Ignore the text in the selection box that suggests that code P applies to 2019, that's assuming that the form is a 2020 form.
It's not clear whether the excess was the result of simply contributing more than the overall annual limit or if you were limited by MAGI. If you were limited by MAGI and in the phase-out range for Roth IRA contributions, the increase in taxable income with the addition of the $55 will likely cause an additional amount of your Roth IRA contribution to be excess and that excess will have carried forward to 2021.
It's generally unwise to have taxes withheld from a return of contribution. Because taxes were withheld, you must enter this Form 1099-R into both 2020 TurboTax and 2021 TurboTax because the income is taxable on the 2020 tax return but the tax withholding is credited on your 2021 tax return.
Amending a 2020 tax return requires using the CD/download version of TurboTax. For those who used the online version of 2020 TurboTax, the amendment software must be downloaded.
