There is no converting to a Roth IRA for a tax year, conversion occur in a particular tax year. There is no way that a contribution for 2020 made in 2021 or a contribution for 2021 can be converted in 2020 because neither amount was in a traditional IRA in 2020. The conversion of these amounts in 2021 are a 2021 Roth conversion.
69VanNuys, TurboTax Product Quality and development folks have in the past asserted that the use for the worksheet as you are seeing it being used is correct, which is why I've generally moved on from this issue.
