If we come up with new theories about gravity, it would be on the foundation of already existing concepts and theories. + Gravity is observable and demonstrable, “apple falls down” will apply no matter our theories on gravity.
Having multiple gods is more akin to “this apple will fall up” and “this apple will fall left” instead of “this apple will fall down somehow”.
But really it goes back to there is no concrete proof of God, but there is concrete proof of gravity so you can’t really compare the 2.