Simultaneity does exist in general relativity, I didn't say it didn't. I said it doesn't exist for things separated by vast distances in spacetime, and that's true. There is no simultaneity for two entities separated by an event horizon.
I don't know what consciousness, as in qualia and subjective experience are, but they seems pretty real and not a buzzword to me, it's basically all I can know for sure exists.
I brought up superposition to explain why I don't consider two mes to not both be me. Both are experiencing the universe through the processes that go on in my brain, so both are me. My consciousness is the program running in their head (yeah, I get our brains are not similar to computers, I'm just coming up with a metaphor here), why can't it be in a superposition of two locations if two conscious instances of my brain exist in the same area?
My thinking is that my consciousness, the set of qualia that make up my subjective experience, "what it feels like to be me", literally is the physical system that is my brain. So if my brain exists, and my brain is functioning properly, then I exist and I'm alive, experiencing the universe.
I can't see it any other way, even if two such brains exist in the same space through some weird happenstance then I guess my consciousness is in a superposition of two locations.