"Can you please tell us your idea of the difference between the power of grace and the power of the holy spirit?"
The Holy Spirit is God. God is power.
And the gospel, which is about grace, is God's power unto salvation but not just initial salvation but the whole Christian life and this is why Paul says by God's grace with him, he worked harder than them all.
By the power of the Holy Spirit, we can know the power of the gospel, which is about grace.