It's pretty absurd to think that every classified document would be handled in such a way. The government simply could not function. It certainly would be dramatic overkill to handle something as banal as a biography of a foreign dignitary.
Appearing on 'Fox News Sunday,' a GOP congressman oversimplifies a claim on classified documents amid the Biden investigation.
www.poynter.org
"Classified documents below the top levels typically are stored, retained and viewed in classified spaces that are not SCIFs, said Bradley Moss, a Washington, D.C., lawyer who works on national security cases. These classified spaces do not have the same security guidelines as SCIFs, he said, though they are more restrictive than normal workspaces."
The operations manager for the National Archives said in the last decade or so, they'd been called 80 times to retrieve classified documents from the papers of former members of Congress when they were donated to various institutions. That simply could not happen in the circumstances you describe.