I believe the Presidential Records Act separates "Presidential records" from "government records."
I read somewhere (today) that a President has permanent access to their own presidential records, and can designate anyone as a representative to handle them, too.
So the question comes down to whether the documents in question were presidential records. I think President Trump says they were, the DoJ says they're not.
-PJ
Actually, the PRA separates Presidential records from personal records. Presidential records under the PRA ARE government records. The former president and/or a designated representative have access to them, but they belong to the government.