After you file

I did get the notice from the IRS and I did downloaded my free transcript (should have included that).  I had hoped to submit a replacement tax return but now understand that is not possible.  I think I will pay what is owed, Construct a new 2021 return, compare it to the transcript and summary 2021 PDF, and if needed will then submit an amended return to get back any due funds.  An amended return I understand is not a revised one, but instead is telling the IRS what specific entries you want changed.   I was just checking to see if I had any other options.  I know I can get  actual copies of my 2021 return but that seems expensive and time consuming.   Thanks