Bo: so that you know

Gd tells Moshe at the beginning of the parsha that he should go (Bo) to Pharaoh, ultimately so that: and that thou mayest tell in the ears of thy child, and of thy child’s child, what I have wrought upon Egypt, and My signs which I have done among them;
There will be a demonstration of Gd’s power, Gd’s ability to accomplish the mission of liberation. A demonstration of how Gd (used to) work[s]

The parsha ends on the same theme of telling: וְהִגַּדְתָּ לְבִנְך ;ָ,וְהָיָה כִּי-יִשְׁאָלְךָ בִנְךָ The events generate a story to tell the children. But in the end, the story includes the sanctification of the animal first born and the ransom of the human. The redemption of the people incurred an eternal debt. Nature has changed so the Israelite firstborn has no right to life. He belongs to Gd.
Actually, the firstborn carries a taint from time of Cain.

Gd’s role in the hardening of hearts is complex. Feeling Gd is with you can steel your will. For Pharaoh, I imagine it was the opposite. What hardened his heart was the idea that he was fighting an absurdity, a fairy tale. Perhaps reason hardened his heart. Reason may compete with Gd, but reason has the advantage of mutability.