One of the things that happens is what you said happens. Which I agree with. I just don't think that's how the writers constructed this season. The way they wrote this was as if the Underwoods changed off camera and that their dilemmas weren't created by an actualization of power but instead with some unaired laundry that we had always been told was aired
Claire went from being a heartless manipulator to a bumbling doofus without any actual struggle that took her from point A to point B.