Trump wanted to weaponize the DOJ. In fact he tried to do it, and succeeded somewhat when Barr was Attorney General. Barr distorted the results of the Mueller Report that found that Trump and his campaign people did some questionable things, such as accepting help from the Russians, during the 2016 election, and that he committed acts that were obstructive, but wasn't able to prosecute due to a DOJ decision not to do so for a sitting President.
He and his supporters in Congress claim the Biden wants to weaponize the DOJ without evidence. Trump will often accuse others of doing what he is or plans to do himself.
As to those classified documents, all he had to do was return them and that would be that. He chose not to after being asked over and over and over again, which is why he was charged with a number of crimes related to those actions. There's nothing innocent about it. It's not special treatment either. A number of people are in jail now because THEY held onto classified materials:
Previous investigations have targeted a former national security adviser and a former CIA director
www.voanews.com
Indeed, if Trump was not a former President and rich, he'd be in prison with the rest of them right now.