I would move the Beginning of Time. As the beginning also marks the beginning of creation. Before creation most agree on nothingness, so the beginning gives meaning to Being the opposition to Nothingness. And what exists between Nothingness and Being to measure them? It’s thresholds.

Thresholds allow for reality to even be. It’s the metaphysical barriers that measure the universe and all phenomenon within, between, and outside of it. So if I had Almighty Magic, I would make the Beginning of Time happen differently. Thus creating a world where I choose the thresholds.

I would create a pocket universe, consisting of a hut in the middle of the forest, surrounded by mountains. I would retire there with my cat and my girlfriend, and leave the rest of the universe to its own devices.

I would create a Pocket Multiverse for myself, my family, friends and acquaintances to use. 

"That's cute." Snaps fingers and erases half of the Totality.

Wait, if we both destroyed half, that means we entirely destroyed our reality. Our universe was not ready for our badassery.

No it was not. ?

I would defend good! I defend all the Weak and sick! I would stand and fight all that is evil!

I'd explore the greater omniverse, restore marvel earth 295 and create special floodgates that would allow changes to these alternate earths. So the Celestials won't destroy them.