OK so you cancelled the Amended return. Good. Is your return back to the way it was originally? You just need to add the 1099NEC income to it and then you can mail or efile it. You can go back in and add or change an anything you want before you actually efile or mail it. Why can't you efile?
Click on Add a State (not Amend) 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 2021, and then select Add a State (you're not actually adding a state, this is just the workaround).
Then when you are ready to file you can try to switch to efile.
https://ttlc.intuit.com/community/e-file/help/how-do-i-change-from-mail-to-e-file-in-turbotax-online...
