Yet Luther’s teaching on soteriology was identical to Calvin’s and Augstine’s and Paul’s.
In what way was Luthers or Cauvin’s or Augustine’s soteriology in any way alike?
Luther’s soteriology evolved through his life and his writings. Which one specifically do you mean? Because in most aspects he strongly disagreed with Cauvin.
And as for Augustine — Augustine held to single predestination (God chooses the elect, but does not actively reprobate anyone - he simply “passes over” them), while Calvin held to double predestination (God choose the elect to salvation, and the reprobate to damnation).