All I can say is that when entering the Form 1099-R into TurboTax you must indicate the amount that you converted to Roth.
You might try deleting and reentering the 2020 Form 1099-R. If TurboTax asks how much of the distribution was RMD, you must say that none of it was RMD. Then indicate that you moved the money to another retirement account and either mark the box to indicate that you converted it to Roth or, if TurboTax does not present that option, indicate that you did a combination of rolling over, converting or cashing out, and enter the amount converted.
