Does a whale have more muscles to control than a human? Is its environment more complex to navigate - swimming through water vs balancing , walking running and

Does a whale have more muscles to control than a human? Is its environment more complex to navigate - swimming through water vs balancing , walking running and jumping? Does it have more bones making its body more complex to maneuver? Are its eyes larger with many more rods and cones, looking at a more complex environment and requiring greater neuron counts to interpret? I think the answer to most (though not all) of these questions is no. Just because a body is bigger doesn't necessarily make it more complex to control surely? For the most part large mammals have the same number of muscles and bones as a small one, and past a certain body size eyes don't get particularly larger. I seem to recall that even very large dinosaurs could have comparatively tiny brains compared to mammals - did they control their bodies clumsily and observe the world much less acutely than mammals? So I have always found this explanation a bit suspect - it is a "just so" story because we observe that whales and elephants don't seem all that smart yet they have bigger brains and bodies but that doesn't make the explanation true by itself. Has there been any actual research that supports the hypothesis that large bodies require bigger brains to control?