What did your hear in Gwen Shamblin’s “gospel” that finally gave you the power to overcome sin in your life that the gospel that she calls “false” didn’t already offer you?
If you got the Spirit of God through obedience, then the Spirit of God was unnecessary.
If you heard that your sin matters, she is right. But just because sin matters doesn’t mean that your salvation is up to you and your obedience. You can be saved by unmerited favor through believing God’s testimony about His Son without the quality of your life making no earthly, Kingdom or eternal difference!
All Shamblin offered you was the gospel of soteriological (salvific) self-reliance. But if you had the power to obey on your own, the gospel that she calls false didn’t undermine this. You can have both! Grace (undeserved favor) and obedience.