Jackson Pollack was a hack. Van Gogh was fascinating as he was one of the first artists not to paint realistically but how he saw the world.
Einstein is held up as a genius because he was near-uncontested in his secular knowledge. He discovered an entire field of physics and science that completely upended everything that preceded it. Werner Heisenberg did the same, but his stuff was more esoteric and less practical so he didn’t get the same attention.