I would find my position to be dramatically reversed if I were to die but my “soul” lived on and I could verify I was actually dead but somehow retained consciousness. (Interesting Twilight Zone on this one.) However, if this fails to happen to me and also to the people who fully expect it to, I regret that I would never have the opportunity to regale in the knowledge that I was right.
If I found myself in a Heaven-like place one morning, but retaining my old personality, my first assumption would be that someone had just created me as a simulation and had implanted the memories of my former life into me.
Which, even if true, doesn’t mean that there isn’t a deity above that creator. But what if that deity is also a simulation…
I suppose it depends on whose definition of God we’re using. My mother is a new-age spiritualist who believes in a spiritual energy that connects all living things. I’m open to the idea that someday, science will discover God the way that Newton “discovered” gravity - as a part of the physical universe that has always existed. If someone discovers the existence of a God-wave or God-particle or God-force that is omnipresent and affects all living beings, and can in turn be affected by them (through prayer, meditation, or emotion), and if this is verified and accepted by the scientific community, I would rescind my atheism.
Proving the Judeo-Christian-Muslim God would be harder, because that God has no identifiable physical form; the scenario most likely to convince me is if I die and discover that there’s an afterlife in which God exists.
Proving the Hindu dieties would be fairly easy, really; if they show up in physical form, especially Ganesha, I’d be convinced.
Most of the Pagan dieties are pretty easy, too. If Thor suddenly shows up and starts tossing lightning bolts around, I’ll believe in him. And if a bull or a swan ever tries to hit on me, I’ll sure as hell start believing in Zeus, the cad.