Jerico

The difference between saiyans of the 2 universes may have also played a part in their power gap. Universe 6 saiyans were stated back during their initial appearance that they did not have tails nor the great ape transformation because of this, where as Paragus mentioned broly taking on the power of the great ape in his normal form. This is a fact that the universe 6 saiyans wouldn't be capable of since they evolved beyond that form. That is why I believe that is the reason broly is stronger then kale