YES----include both checks. If you enter an incorrect amount it will delay your refund while the IRS has to cross check and recalculate the refund you see on your Form 1040.
Congress passed the 2nd stimulus bill at the end of 2020. Both stimulus checks were an advance credit for your 2020 tax return, The 2nd stimulus checks started going out at the very end of December 2020 and continued into early January 2021. When you fill out the recovery rebate credit it is important for you to enter the entire total of the amount you have received for yourself, your spouse, and your dependent children so far. Entering the wrong amount might delay your 2020 refund.
It should help you if you bear in mind that the purpose of the question is to determine if you have already received the amounts you should have received.
You do not enter anything at all about the 3rd stimulus check.