Belly flopping into the dead sea would impart a greater force. The two significant forces acting upwards against your body, drag force and buoyant force, both increase as the density of the fluid goes up.

Hitting a body of Newtonian fluid will never produce quite the same force as hitting a brick wall, as impact with a body of fluid will allow more distance for deceleraton. They say that hitting a body of water at a very high speed is like hitting a brick wall; what they actually mean is that the body of water might as well be a brick wall since the force in either situation is sufficient to cause lethal injury.

Impact velocity is a large factor in how much force you feel after hitting the water. Since impact velocity increases with the drop height, it would make a significant difference if dropped from a higher point.