Do i have to claim RMD as income in 2020?

If you had a distribution in 2020 and did not roll the distribution back to the same or another retirement account then the taxable amount of the distribution is entered on your tax return as ordinary income.

Yes, if you kept the money and did not roll it back as permitted for 2020.   It was not actually a RMD, just a distribution that the CARES Act allowed you to roll back before Aug. 31, 2020.