Suppose we admit: of course we're living in a multiverse simulation, the double slit experiment clearly and consistently shows that. How can observing a particle or not change it's outcome? How can a single particle interfere with itself? The superposition principal is a model, like dark matter/energy and the big bang, it's a model to explain strange things like a placeholder. The truth is we cannot know the reasoning behind some strange things, others we develop better models for later, some are very consistent so we call it a law.
Then this is a simulation, and not only that, you have power over it. Manifestation is what some call that power over it. Synchronicity is another indication. Combine the two and you are staring at clear evidence but to believe it means you become very disappointed because it's inconsistent so you just call it coincidence and move on, regardless of the evidence.
Tulpamancy is like this for me, things happened that couldn't have happened given the singlet model of the mind. Obviously the mind holds many personality potentials, actors do this as part of their profession, infinite parallel consciousnesses even, summonable on a whim and fluid not discrete.
In the absence of conditioning, there is no static definition of ego, though personality seems more resilient. What we are seems to be not the brain, not the body, not the sum of our experiences and conditioning, that's the ego or the NPC side, the OS or hard coding, but it can be changed by further conditioning, un-conditioning, etc, so what are we? Perhaps a personality, perhaps only a personality, and perhaps that personality was tainted by life and can be cleaned of traumas, and there doesn't have to be only one. Soul or not, I don't care, that's not something you interact with here, we're just apes here, the personality though seems to be something many other animals have along with us. It may be the thing that thing we built from experiences, but preferences seem to be irrespective of experience to some degree. Is that personality above the game? Is it the thing that experiences all simultaneous realities? Is it the part of our higher self we do see?
Imagine we fluidly transition though infinite parallel universes on our whim, traversing as we see fit, living a pathway that's arbitrary through infinite, even locally deterministic, universes. Our free will is that path, cut like a line through a plane, like a plane or surface through a solid, like a cube or three dimensional topography through a hypercube.
What can we do with this? Nothing really, it doesn't matter in the end, all is arbitrary here in my opinion.