Of course he had them after he was out of office. They date back to his days as a Senator, and he was out of office for four years during the Trump years. Joe Biden was casually removing classified documents and taking them home for years, maybe decades. He only ‘cooperated’ when they were discovered. He is still under investigation by a special prosecutor for this, btw.
As far as I can tell, Bill Clinton did not take home classified documents. But his Chief of Staff Sandy Berger was caught with documents from a secure facility tucked into his pants. He was charged and convicted, but got a slap,on the wrist for what seems to me to be the worst document violation of all, as it shows clear intent to surreptisiously remove classified documents.
This is not to minimize what Trump did. He is unique in that he continued to play games with the documents and obstruct justice. He deserves to be convicted of a felony and should never be president again. But years in jail given the precedents would be crazy.