He is. He's a very cerebral QB who knows the Shanny system inside and out.
He's a touch/timing passer who throws the ball to a spot BEFORE the receiver makes their break. That catches the defense completely off guard as they have no idea where the pass is going. Thats why the passes he throws are wide open. The defense can't predict where the pass is going.
Brady, Montana, Peyton were passers like that although it may be a little premature to compare Purdy to those greats.
Josh throws the ball AFTER the receiver makes the break which allows the defense to converge on the ball. The defense knows where the ball is going. This forces Josh to throw the ball in tight windows with the defense on top of the receiver. This also forces Josh to throw the ball a 100mph to fit it into a very tight window.
The weapons argument is a bit silly as all QB's need great weapons.
What would Josh be without Diggs, or Mahomes without Kelsey or Burrow without Chase/Higgins ?