When you say that God exists outside of time and space: how do you know?
God is often equated with light; Light of the nations. Light travels at the speed of light. If plug the speed of light, into Special Relativity Equations of Einstein, we get a reference where the universe will appeared contained in a point, with time essentially stops. The mass variable of Special Relativity becomes infinite relativistic mass, which does not or can exist within our finite energy space-time universe. We do not have the instruments to meet all the criteria needed to see God, if he was sitting on the speed of light reference.
God would exist where space-time; see above, becomes discontinuous; into separated space and separated time, but without mass; not of any mass based realm.
If God could move in space, apart from time, he would omnipresent, like the tradition; distance potential=1 and time potential=0. The ancient understood separated space and separated time much better than does modern space-time science. This is the future of quantum physics. If you can control time and space apart from each other; via space-time, a new frontier opens up.
If God could also move in time apart from space, would know the past, present and future at any point in space.
If God decided to become omnipresent; distance potential=1 and time potential=0, while also moving in time with distance held constant; time potential=1 and distance potential=0; sequential but a disconnected sign of the cross, this would makes him omnipresent and omniscience. This was ancient math and infinity personified.
I developed a theory called the MDT theory about 20 years ago; mass, distance and time. It came as an inspiration and was solidified as a series of diagrams I created in PhotoShop, that set up framework for an extensive math model possibility of reality in just three variables. These diagrams looked like concentric circles, where you can could adjust the three parameters; M, D, and T like dials, and solve complex connections between space-time and separated space and separated time; macro and quantum worlds meet.
I was not sure back then how to explain this to justify and explain this model, in the Physics Forums I used to write in; answer without a solution. The 6-8 diagrams; dials, in 20/20 hindsight were connected to the effect of separated time and separated space on space-time. The logic of the model led to many new things yet to be discovered such as six possible universe formation scenarios. The MDT theory was named after the scenario that was closest to the modern BB. There are five other ways from separated space and time.
In the MDT scenario, once mass appears in the universe, we finally have a capacitance for space-time, that is sustainable and scalable; from from subparticles to the galaxies. Energy can induce space-time, but it is not moldable like mass and matter, except in black holes. However, the black hole limits the formation of the chemical life we see and need to account for. With the appearance of mass, separated space and separated time interacted, at the quantum level, with the ever changing scalable and sustainable levels of matter in space-time.
I put D before T ; MDT, or distance potential before time potential, after the mass of the primordial atom appears; particle matter. This distance potential is for an almost omnipresent universe; blueprint in space. Then time is added to build from the blue print, in time. The model could dial in the details. The model also paralleled Genesis; brooding over the deep; distance potential and blueprint, and then let there be light; d/t=photons. blueprint divided by time, as steps in time.