The phone conversation with a TurboTax support person said I could use TurboTax to do an amended 2022 return which would generate the Form 8606 and mail, not e-file, it. I did this very easily and TurboTax nicely completed the 1049-X and Form 8606. I had read mixed answers about filing the Form separately or no, and fret more comfortable filing it with the 1049-X, so TurboTax was very helpful.
