The only way to reduce the propshaft angle, using a rigid shaft, is to move the motor as far forward as possible.

In your case that would be major surgery as the deck will have to come off, or at least the hatch should be extended forward.

The motor would have to sit on the wood, as low down as possible.

With this size boat the bouncing (called porpoising) will stay, unless the angle is reduce significantly.

Regards, Jan.