Even if TTX allows e-filing 2019 amendments later, once software opens back up again....I'm not sure we really know if TTX will allow you to e-file your amendment......since you filed your 2019 taxes elsewhere...
1) You would need the 2019 desktop software
2) You would first need to re-create "EXACTLY" what you originally filed elsewhere.
3) Then you pretend to mail file it with the desktop software (since 2019 can't be e-filed anymore.....and since you've already filed elsewhere) ...and then only then run thru the Amend process to make your changes.
BUT I haven't seen anywhere that TTX would ever allow e-filing the amendment in your situation, even if e-filing amendments was still active, since you didn't e-file the original 2019 tax return with TTX.
But that's just my considered skepticism about what might be involved.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
