I come down on the side of time not existing, but with a caveat; Change is time and Net Future Usefulness (net useful change) is the core reality. Anything that exists does so because its existence is net useful to something else (even if that is its own future existence). Some combination of input vs entropy vs chance is interacting for persistence' sake. That persistence is the underlying ends of all means. Evolution is a macro version of quantum foam. Time emerges from the process, as does gravity so that the two remain connected quantitatively. Gravity comes from mass persistence and mass persistence comes from net change, which can only happen as discrete events over time (in this universe). As the t-shirt says, "Time is what keeps everything from happening at once.", but the reciprocal is also true: Everything not happening at once is the source of time. In previous iterations, perhaps everything happened closer together, or there was only one previous iteration where everything happened without time, but it broke the structure and time flew apart, carrying the other 3 dimensions along. Gravity is then just Time trying to pull everything back together, or being reflected back from the impedence mismatch of Everything against Nothing.

In the meantime, the ruling functionality is Persistence dependent upon self useful patterning (Life vs Entropy, contribution vs consumption, matter vs antimatter, emergence vs chaos, structure vs randomness).

aka Net Future Usefulness