I need to amend my 2020 return. I'm not finished with it! I've paid for it so I could print it and look at it. I haven't e-filed, says I can't amend it and need 1040x?

When trying to amend my 2020 return which was not e-filed and will be mailed once I am actually finished with it, I get the message: It looks like your federal return can't be amended right now
You're going to have to wait until the tax form for amending a return (Form 1040X) is ready for processing.
Form 1040X will be ready on 03/25/2021.
How can I access and amend my return which has not been e-filed, and why can I no longer access it all of a sudden for amendments when it will be printed and mailed once it's actually done and correct? It shouldn't have been sent to the IRS by Turbo Tax since I did not and could not e-file so why is Turbo Tax preventing me from making changes? I've paid them $75 for my online Turbo Tax, and I can't use the service before I'm finished with it. I don't have any PDF altering software to edit the PDF that I can download of my return that need alterations prior to mailing to the IRS.