To clarify, the withholding is not part of 2021 or 2022. It was part of 2020 tax pre-payments to be applied to the total tax owed that year, the same as any withholding and estimated tax payments. There is no carry forward of withholding. There can be "let it ride" on the 2020 refund, of course 🙂 Then it would apply to 2021 taxes.