The Knights are weirdly powered, the Swords allow them to chop up a Titan, but not to harm a street thug. In Grave Peril Michael, sans Sword was still able to generate a repulsive effect to the Rampires suggesting it isn’t all the Sword, something confirmed in Little Things, his presence healed a child so he has a direct line to the almighty, something Murphy did not.
It will be a thorny question adapting the White God, I actually think Butcher has handled it well with the books, initially your not quite sure whether Michael is a nice lunatic with a magic sword or the real deal. It’s the way he interacts with people at the party which shows the latter, his faith is a genuine thing to him, and they the monsters accept it.