If you bought from Amazon that was the Desktop program. Did you install it and activate it? It is separate from your Online accounts and returns. The only copy would be on your computer and not saved online. What did you use for 2020? You probably used the Desktop program for 2020 if it transferred it into 2021 or you would need to have downloaded the .tax2020 file from Online.
To Amend in the Desktop program you need to have the .tax2021 on your computer. Can you open your return in the program? After you open your return first MAKE A COPY to amend. Go up to FILE-Save As to give it another name.
How to Amend 2021
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-2021-return/L1gEU4G3X_U...
If you did use the Online version for 2021 (since it transferred from 2020) then click on Add A State to let you back into your return.
