You are missing the point. You cannot talk about classification and de-classification when it comes to the POTUS without talking about his broad and unilateral discretion to declassify anything at any time. He doesn't have to keep declassified documents in a SCIF or any kind of filing cabinet. He doesn't have to make a list. It doesn't matter if his aids remember anything, although Kash Patel does remember. But it doesn't matter if none of his aids remember, because he doesn't have to tell them anything.
You might want to read the Presidential Records Act of 1978 which was amended in 2014.
https://www.archives.gov/presidential-libraries/laws/1978-act.htmlWhat is the definition of records under the Presidential and Federal Records Act Amendments of 2014?(2) The term “Presidential records” means documentary materials, or any reasonably. segregable portion thereof, created or received by the President, his the President's immediate. staff, or a unit or individual of the Executive Office of the President whose function is to advise. Dec 11, 2014
8. Could Trump have declassified the removed documents?
Presidents do have ultimate decision-making power over the classification of documents, and Trump could theoretically have declassified any records he removed from the White House. Indeed, former Trump National Security Council member Kash Patel has claimed Trump did just that before leaving office. There is no set procedure for presidential declassification, meaning that could be the basis for a defense if a case proceeds against Trump. But
even if Trump was found to have declassified documents, he could still potentially be prosecuted for removing or destroying them. And Richard Painter, chief White House ethics lawyer under President George W. Bush, points out that declassification of documents for an improper purpose could be a crime in itself. “
If he declassified documents in order to remove them and destroy them, he’s destroying evidence, and that’s obstruction of justice or obstruction of Congress,” Painter said.
https://www.congress.gov/93/statute/STATUTE-88/STATUTE-88-Pg1695-2.pdfQuestions and answers about automatic declassification;
https://www.justice.gov/archives/open/declassification/declassification-faq#:~:text=EQUATE%20AUTOMATIC%20DISCLOSURE%3F-,No.,disclosure%20of%20records%20or%20information.
Public Records Act:
"Every president, when they leave office, those records that have been created by the president and his staff are presidential records that go to the National Archives," Baron said. "
The owner is the American people."
The PRA thus makes clear that only the United States (and not former President Trump) owns and is authorized to possess and control the presidential documents.
The PRA gives a former president certain rights to access and limit access to the documents in the possession of the United States, but
it rules out the possibility of a former president possessing presidential records after his presidential term.This includes all presidential material, whether it's routine, unclassified notes or top-secret national security documents.