Wonder why?
As the Supreme Court ruled in Navy v. Eagan, the President’s plenary authority concerning classification and declassification of information flows directly from Article 2 of the US Constitution. He alone does not have to “play by any rules.” Furthermore, upon leaving office, he retains his highest level of security clearance forever, and is entitled to daily national intelligence briefings, also forever. Upon leaving office, he can take with him whatever he likes. While still in office, he can declassify anything simply by saying that he did – and he did “say.” He also left various written directives. These still have the force of law.
In short, it is impossible for the President or a Former President to “break the law” concerning whatever classified information he may have in his possession. Even if you speculate that he is “doing a Pelosi” by taking advantage of classified secrets, that’s just idle speculation.
The only people who might have broken the law are the FBI agents who pored through these documents and took them out of a secure facility (Mar-a-Lago …), even though they themselves did not have the appropriate levels of clearance to do so – namely, “the very highest.”
Mar-a-Lago has a “SCIF” secure conference room for the handling of classified information. Trump used it many times while in office and it’s still there. If some documents were locked in a storage room, instead of the SCIF, it implies that they had been declassified. But in any case, Mar-a-Lago, which is continuously protected by Secret Service, is “a secure facility” in its entirety: even a storage room is “secure” for classified information handling purposes. Even the hallway. All of the prescribed procedures were followed – except by those agents.