Prove that! Two years you’re still squeezing poop
There is enough proof right here to impeach Trump right now. Given a bit more time, Congress could very well demonstrate to the American people just how
HUUUUGE the "no collusion, no obstruction" lie really is. Just let Mueller sit down with a few pointy questions from someone like Kamilla Harris, or Adam Schiff, or one of the other senior prosecutors available to ask the right questions.
Furthermore, you're going to have the testimony of Mueller's staff, those "17 angry Democrats", who have no agenda or interest in protecting or shielding this President or his party from the consequences of their action, are also going to be testifying and Trump and his staff will not be able to control what those witnesses say. Mueller, being a super straight arrow kind of guy, would be less direct in his responses, as he was in his report.