Correct.  There is no RMD to satisfy for 2020 before doing a Roth conversion in 2020.

Thanks, I believe you, but is this documented somewhere (e.g. IRS) ?

From the IRS:

IR-2020-162, July 17, 2020
"Since the RMD rule is suspended, RMDs taken in 2020 are considered eligible for rollover. Therefore, RMDs can be rolled over to another IRA, another qualified retirement plan, or returned to the original plan."

It would have been more correct for the IRS to have said, "Since the RMD rule is suspended, [distributions taken in 2020 that would have been RMDs were it not for section 2203 of the CARES Act] are considered eligible for rollover. Therefore, [these distributions] can be rolled over to another IRA, another qualified retirement plan, or returned to the original plan."  I guess that that's a bit too wordy for them, though, so they simplified it by using "RMDs" to refer to  distributions that are not actually RMDs.  It a bit of an oxymoron to refer to a distribution as a non-required required minimum distribution.

Also be aware that the section 408A(d)(3)(C) of the tax code defines a Roth conversion as a type of distribution and rollover, so this statement by the IRS regarding rollovers applies in the same manner to Roth conversions as it does to ordinary rollovers.