It’s interesting how it’s not turtles all the way down (as I understand it at least). The things you learn of one scale do not completely translate to the next but serve as the “shadow” projected by the next level down the line. And this probably brings up the complexity that lets us exist and perceive. I say probably because who knows what else is going on in the universe.

All this to say who knows if we are ever going to learn the fundamental why if there is one.

There is no notion of causality in our laws of physics, and from all we know gravity could certainly be different, or absent. You could have a universe with just the other three forces.