Some of those documents were SCI–Sensitive Compartmentalized Information. That is WELL beyond “Top Secret.”
I once handled SCI information when I was in the Navy, and I can tell you that a guy brought me the documents, waited for me to get done using them (maybe he went and got a coffee), and then took them away when I was done with them. And this in a formal Naval office with an O-6 there in charge (I was a lowly O-3). Within sight of a HUGE Naval base.
The fact that Joe Biden had these documents outside of certain areas and outside of proper surveillance is itself a crime! And a very serious one, at that.