It's common to end up with multiple accounts. First LOG OUT of whatever TurboTax account you're logged into right now. Then use this TurboTax account recovery website to get a list of user ID's for an email address. Run the tool against any email addresses you may have used
https://myturbotax.intuit.com/account-recovery/

If you used the Desktop CD/Download program then the only copy is on your computer and not saved or stored online.

To get back into your return.  Do not click on Amend!

Click on Add a State to let you back into your return.

From Tax Home (the first screen you see after you sign in), scroll down to Your tax returns & documents. You may have to select Show to open the drop down.

Select 2020, and then select Add a State (you're not actually adding a state, this is just the workaround).