Why was Manafort only charged with crimes he committed years before meeting Trump? Didn't the report say Trump cooperated fully until he learned he was wire-tapped and the subject of the investigation. Once he knew he had dirty cops like Comey leaking, lying and filing false reports, of course he began working through lawyers.
Bottom line, the Muller report did not find Trump colluded with Russia. That is why the Muller report did not lead to impeachment or charges against Trump.