Interesting. I did not see any mention of e-filing amended returns was for "certain paid tax pros" only in that article. So I assumed it was intended also for us do-it-yourself type users.
Also, I would have guessed TurboTax would have barked at me if I was doing something that was not supported. Instead TT allowed me to make the changes and TT also filed my amended return without complaint. The filing attempt failed and now I have lost online access to my 2020 forms.
It sounds like I have no other options, so I will manually file my amended return.
Thank you for your help.
