This is exactly the problem, and the key difference between this, Biden and Pence. Trump had 'holy of holies' documents with sources and methods just lying around, and was showing them to random journalists who are not known for keeping quiet. The whole thing was an espionage gold mine. He could have done the right thing, like Biden and Pence, and quietly returned the information to protect it.
Instead, Trump blabbed about it, engaged in a protracted court fight that told absolutely everyone he had the information, and did nothing to protect the material. For all we know, any tampering with surveillance footage was done to cover up the fact that the documents were accessed by an intruder. Now we have a major problem with any intelligence sources covered by the documents, because we don't know whether they've been compromised and flipped.
All of those information sources have to be taken with a giant grain of salt now, if not written off as a pure dead loss. Ditto for any war plans. The best analogy is that Trump was an oblong-ball coach who ripped pages at random from a copy of the playbook, and left them in the opposing team's locker room. He would be fired, and blackballed from the profession forever.
Trump severely jeopardized national security through his actions. The only question left is whether he's a foreign agent, or an idiot. The most coveted cover for a spy is an idiot. No one suspects them, governments are full of them, and other governments can't monitor every idiot.
It's also worth noting that neither Biden nor Pence would have been in the loop on sources and methods more than once in a blue moon, if ever. It's also a big difference when it comes to any audio tapes Clinton legally kept. He would not have been discussing sources and methods, and he would have been guarded about just how much we knew in a phone conversation, to avoid compromising information flow.
It's a wonder Allen Dulles hasn't crawled out of his grave and strangled Trump to death.