Don't file an incorrect Form 1040-X
since you have to file on paper anyway, the simplest path is to get Form 1040-X in fillable PDF from IRS.gov and make the entries yourself.
Do not attach your old 1040 nor your revised 1040 because the Form 1040-X reflects any changes there and becomes your new tax return.
Instead attach Schedule 1 showing the correct IRA contribution.
New schedule 1 should be showing in your revised turbotax return.
