The point that everyone is missing is that any President, has access to the top of the top secret food chain. They has top level access to all types of information. What is the difference if this data is in their memory or on paper, since it is the same data?
We do not erase the memory of the President when he leaves office. If any President was up to no good, for personal gain, their word would still be worth money, even without documents. This is why ex presidents get paid big bucks to lecture. They can skate around and still give out some useful information.
Classified documents is more often about sentiment, about a particular important time. It is often kept as a keepsake, and usually ends in their Presidential library or in boxes in the closet, with old photos.
In the case of Trump some of the assumed classified documents were harmful to the Swamp, which is why they made a stink. They could use their lawyers to deny Trump's memory. But they cannot hide from hard intel about Hunter and his laptop, written on official stationary, that has signatures and can be verified. This would be damming evidence, beyond just the memory of the document.
If you look at the ordering of document secrecy classifications, it begins with Confidential, next is it Restricted, then we have Classified, then we have Secret and finally we have Top Secret. Classified is sort of chump change, to someone, like a President who deals in Secret and Top secret. But if you are out of the loop, even confidential sounds very important. You will not see Confidential without low Low level security clearance.
If all you had was classified documents, you would not have all the best stuff than enemies crave, which is secret and top secret. You would have more like day to day operations, behind the good stuff, that will someday be de-classified. I doubt would either Biden or Trump would be cavalier with Secret and Top Secret data, since both in their own ways, are loyal to the country and neither would betray it.
But some of the meetings during their tenure, may be eventful to them, and they may wish to preserve these through the original documents, way outside top secret Q-area documents. Nobody has accuse either of Secret and Top Secret documents, so what is the big deal for a President, who know way more, other than the optics of politics. This is small change for a President. The Swamp Democrats started this nonsense. So what comes around should be able to go around. The Left is now finding common sense, they lacked during the coup.