Perjury for corrupt intent
I don;t know about that. Cohen is charged with lying about business deals. I think you have assumed there is a crime looking for a coverup. Business deals with Russians is not a crime. Secret business deals with Russians is not a crime. Lying to the public about secret business deals with Russians is not a crime.
What is a crime is if there was a conspiracy between the campaign and the Russians. If the Trump Tower Moscow deal included provisions for the Russians helping Mr Trump win an election, then we have all of the above. But the filing does not say that. It says Cohen was approached with nefarious provisions but the deal was dropped. Cohen lied to the FBI about it ergo his charges.
Unless more is known, Cohen just got caught lying.