It should be obvious to everyone that the Browns receivers are getting FAR more separation than are the Jets receivers. It's hard to tell how much better Mayfield is playing than Darnold as a result.
He's a tall skinny version of Dedric Ward, the guy you take a couple deep shots a game with but mostly there to take the top off the defense creating room underneath for Enunwa, Pryor, Kearse and company to operate.