The IRS already knows what you received for the Recovery Rebate Credit, they will most likely correct the error on your return. The IRS would then send you a letter explaining the change they made. Wait until your return is fully processed (refund received or payment deducted) by the IRS to see if it gets corrected.
DO NOT file an amended tax return with the IRS to correct an error you made in calculating your 2020 Recovery Rebate Credit.
