Trump is using the PRA as an all-purpose Get Out of Jail Free card. It doesn’t matter to him that he wasn’t charged with a violation of it. Nor does it matter whether the documents were classified or not. He’s insisting that he could willfully retain anything he wanted because he was President.
Maybe no lawyer could get away with that argument in court but Trump’s audience is his base. To them that is a sound and viable defense. Only liberals would deny a President the right to do what he likes to his own documents. The technicalities of the charges are typical elite bullshit. Trump looks better for having the documents and the more that liberals carp about them the worse they look.