Cohen is a known liar, I wouldn't make any conclusion off of what he's said.
We can actually make some conclusions about what he said. He said two basically contradictory things, Trump is not guilty of certain crimes, and Trump is guilty of certain crimes. We can determine right away that one of those two statements are true and the other false. So now we need to give the statements a weighted odds of being true. By themselves and with no context we have no real way to decide, but lucky for us there is a huge amount of context we can draw on to make this decision. For example Cohen himself has been found guilty of participating in some of these crimes, so we know at least that the crimes were committed. Then we know that Trump has a whole lot of people around him that are being convicted of similar crimes. Then we have a whole slew of other, often circumstantial, evidence of crimes around the President, which by themselves would not make a very convincing argument but when added together, and to the statements Cohen made and the other crimes we are seeing other people in Trumps circle being convicted of do add up to some convincing evidence. Sure, no one thing is a smoking gun, but this is not a Perry Mason show. Real life rarely has that one damning piece of evidence. In real life cases are made up of lots of little pieces, and Trump is awash in a sea of it.
Certainly we can all agree that if there is strong enough evidence against Trump, we'll see charges brought, right? So far we're years into an investigation and there is no evidence of collusion and no charges.
We don't know if there is any evidence or not, because the investigation is still ongoing so the evidence, if there is any, has not been released yet. Charges come after the investigation.