Under you soteriology it becomes a "metaphore". God has no action or part except to acquiese to Pharaoh's decision? Yet He specifically states:
There is no "metaphore" in any of this. What most people do to explain the God of the Old Testament is 1) to ignore the Old Testament or 2) reduce it down to moral stories which is what you are doing.
Sorry. God interacted with people in the Old Testament exactly the same way as in the New. There is no difference. He's in charge and He'll do what He pleases. I happened to believe both conditions are true, that God and Pharaoh both hardened Pharaoh's heart.
In the scruipture it is a metaphore. "Heart" is metaphore for predisposition. You read it metaphorically as well, as you surely don't think that something physiologically changed in the Pharaoh's heart muscle. Yes, God played exactly the role the Scripture describes: He hardened Pharaoh's heart as well as Pharaoh hardened his own heart, and after that change of heart the Pharaoh persecuted Moses and his people. God predisposed and the Pharaoh disposed, in the way contrary to the will of God.