You could not have amended the 2020 tax return since the original tax return that you filed has not been accepted or rejected by the IRS.
Once a tax return has been filed it cannot be changed, canceled or retrieved
You will have to wait for the IRS to start accepting or rejecting 2020 tax return on February 12, 2021
If the return is rejected you can make the necessary changes and e-file again.
If the return is accepted you will have to amend your original tax return. An amended return, Form 1040X, can only be printed and mailed to the IRS, it cannot be e-filed. The IRS will take up to 16 weeks or longer to process an amended tax return.
Before starting to amend the tax return, wait for the tax refund to be received or the taxes due to be paid and processed by the IRS.
See this TurboTax support FAQ on amending a tax return originally completed and filed using the 2020 TurboTax online editions - https://ttlc.intuit.com/community/amending/help/how-do-i-amend-my-turbotax-online-return/01/27577
you are really messing up your 2020 taxes. you aren't supposed to file an amended return until the previous one (in your case the original filing) is fully processed. TT is holding your returns until the IRS actually opens e-filing on 2/12/2021. having already filed both original and amended returns it's anyone guess as to what will happen.
at this point do not file another amended return until your previous filings get straightened out.