Dual state time: only input state and output state if the universe transition function exist. Global single state time: the universe transition function alters the present state in-place all at once. Local single state time: only one bit changes at a time.
We can already deduce that spacetime cannot be fundamental, i.e. it does not exist. You are referring to an outer substrate, but we need something like this anyway. And no, I have no idea how we bridge the semantic distance to the void.