Space

Ultimately, physics follows the maths, everything else is interpretation to comprehend what the maths is telling us.

In relativity, gravity is a smooth, continuous distortion of spacetime. In QM, gravity is just another force, mediated by the graviton. Both theories are consistent with the known maths. The fact that they don't agree shows the large hole we have in the maths.

In short, we don't know what gravity is. Then again, we don't know what most things are, once we did deep enough. We just have maths, with interpretations that let our monkey brains make sense of them.

My favourite example ample of this is the "dark sucker theory". Envision a universe where light producing objects don't produce light, but suck up dark. We can make the model work for our universe. The reason we don't use it is due to it being harder to work with than the light emitter model. Another one is the rabit hole of what relativity says about the existence of light (hint light doesn't exist, from light's point of view).