If he could convince himself letting the Rhineland go was an acceptable sacrifice, there's not really much in the way of a similar decision for Hannover, for once. I could see him doing some mental gymnastics to convince himself it's the right thing for Germany, if not for Prussia.That's true, doubling down on it is definitely something he wants to try. Though he also isn't entirely comfortable with supporting more breakaways because he is still a Prussian supremacist. But yeah it will be a useful trick.
I could also see his faith on Prussia being shaken by the Osthilfeskandal, and the Junkers being uncooperative assholes.