The IRS has never specifically addressed this issue with CRDs and other types of disaster distributions which are handled similarly on other types of Form 8915. The industry consensus is that performing a Roth conversion with a CRD is not permitted because depositing the distribution into a Roth IRA would not constitute "repayment" of the distribution as defined in the statute.
Further, there is no way to accommodate such a transaction on Forms 8606 over multiple years. The only way to be able to report this as a Roth conversion is to not report it as a CRD and report it entirely in Part II of the 2020 Form 8606. As such, the entire amount is taxable in 2020.
