How many gospels save the soul?
All of them, Rom. 3:25's "remission of sins that are past, through the forbearance of God."
Fact is that no matter how some might go back and forth with one another, some are married to their understanding; some will be married to a sound understanding, some will not be, and never the twain shall meet, until there "first be" an "all readiness of mind," Acts 17:11.
At some point we each have to begin to ask ourselves on a regular basis 'if I was off about (this, that, the other) what else may I have been off about; what else might I be better off revisiting; and how might I approach doing so, afresh?'