I’ve long suspected that the intent Trump had for taking and keeping the classified documents was that, as has been reported from different sources, he had a habit of using classified documents as note paper, writing notes in the margins. Comment on this practice was made when the need for a Special Master was discussed.
The idea that those notes detail planning for the Jan 6 debacle, planning to overturn the election results, or other incriminating plans would explain why he would not return them and has fought so hard to claim they are his.
He claims he declassified them. Perhaps, in his mind, his using those documents as note paper was de facto declassification (that really doesn’t work for me). He also claims the Presidential Record Act (PRA) gives him the right to keep those documents. Like the declassification claim, this is also absurd.
The PRA was written specifically to prevent a former President from keeping such documents and it seems Orwellian to try to use it justify his keeping them. However, if the notes he made on them were not a part of his Presidential Duties then they would be personal records and the PRA has been used to allow former Presidents to keep their personal records.
So, there doesn’t have to be any espionage intent (although that wouldn’t hurt). This could also explain why he officially did not make the argument that overturning the election was a Presidential Duty to get the Georgia case moved to Federal Court. Making that claim in a court document might undermine his argument that those notes are personal records and not part of his Presidential Duties.