Actually, the grip doesn‘t have nearly as much impact over spin than what people think. It‘s that spin is produced by accelerating the edge of the ball (the top edge forward in your case) and you do not need to hit very vertically and make a contact right behind the ball. You can hit the upper edge of the ball by giving your string bed a slight forward tilt. Instead of presenting a face that is perpendicular to the ground, you can close it a little.
With the exact same horizontal swing path, you‘ll get more spin and less pace. If you get your swing more vertical (prior ball contact), you‘ll send the ball higher over the net and you‘ll get only a marginal amount of additional spin.
Pros might seem to swing very vertically, but much of that upward movement occurs once the contact is made.
As for your grip, it might influence your swing a bit, but not much and it won‘t get you free spin necessarily if you get a more extreme grip. You are better off working with what you have and trying to nail that WW finish properly.