From where I'm sitting, it looks like death should not be the end in that case.
You can't perceive the passage of time when you are dead, so you're just going to experience dying and then immediate rebirth after the countless eons pass for that rare moment where entropy spontaneously reverses to form your mind again.
None of this establishes it is subjective in the slightest. The reality we experience just is. Of course it is not equivalent to quantifiable data. If I go see the Shanghai Tower in person, and if I look at a picture or a written description of the Shanghai Tower, of course the real thing is categorically different than the thing in reality. How does that demonstrate the real thing is "subjective"?
The real thing is not subjective, but it is perspective-dependent. The physical sciences allow us to describe all possible perspectives, as both general relativity and relational quantum mechanics are perspective-dependent theories. But there is a categorical distinction between a description of a perspective and the reality of a perspective.
No matter how detailed a description of fire becomes, the paper it is written on will not suddenly burst into flames, as if it becomes a real fire. The reality of a thing, and the description of a thing, are always distinctly different. The physical sciences are descriptive, we can describe all possible perspectives, but there is still a categorical distinction between the reality of actually occupying such a perspective.
It makes no sense to ask how to quantify the reality we experience. It is false to qualify it as well. Reality just is what it is. When we assign quantities and qualities to it, we are moving beyond reality and into interpretation of reality. Reality does have the property that it is capable of being quantified and qualified, but the specific quantities and qualities we choose depends quite a bit on contextual factors and only makes sense in relation to social institutions as all object-labels are socially constructed norms.
This is, again, true for all objects. There is no reason to separate "the experience of seeing color" from any other experiential realities, such as "the experience of seeing a cat" or "the experience of seeing a triangle." Perspectives are defined in terms of physical systems, and so by definition two different physical systems occupy different slices of reality from two different perspectives. The only way to make them share the same perspective would be to make them the same object, which then they would no longer share the same perspective because the original two objects would no longer even exist, definitionally.
It is just fallacious to jump from reality being perspective-dependent to it being subject-dependent. You have not actually established some fundamental role for subjects here. Again, the physical sciences allow us to describe reality from all possible perspectives of all physical objects, so there is no physical reason to state that reality only exists from human perspectives. If you want to point out the fact that you only occupy the reality of your own perspective and thus cannot actually verify the reality of other perspectives described by the physical sciences, sure, but this is also true of other people. You cannot occupy, as a matter of definition, the perspective of other human beings, so you would be forced to conclude that the slices of reality corresponding to other human perspectives don't exist, either, i.e. devolving into solipsism.
Are you a solipsist? I guess I never actually asked.
If consciousness is a quantifiable object (which is necessary to be in a superposition of states which is a mathematical statement) then you should be able to give me a definition of consciousness I can quantify. You have yet to do so.
You have no mechanism for this to actually occur. You are just devolving into complete quantum mysticism, believing if you abuse terminology from quantum theory then suddenly it gives it legitimacy. It does not.
Stating that if two identical objects exist simultaneously they would be in a superposition of states is making a very specific quantifiable physical claim which you have not even attempted to explain the possible physical mechanism.
No, qualia is just a category of objects. Things like "redness" or "loudness," these are socially constructed norms we use to identify aspects of reality in a way that allow us to communicate them to other people. There is nothing special about "qualia" over any other category of objects, such as mathematical objects or physical objects. Experience itself is not a category of objects, it is not "qualia," nor is it "subjective." What we experience is just reality as it exists from our own perspective.
I'm not a solipsist, I'm not an anything -ist, I've never seriously studied philosophy, I'm just a person trying to make sense of why I as a collection of atoms just like everything else in this universe have an experience at all. Why is there a feeling to it? "It" is all I can for sure verify, you seem similar to me so I grant you have "it" as well as animals with brains and such. I generalize this further to everything else around us, that surely they too also have an innate feeling of existence, maybe perhaps just one far simpler than the sensations dreamed up by living organisms.
Again, my point is that (1) we can describe reality from the perspective of any physical object in the natural sciences, independently of whether or not it is a mammal with a brain, (2) I can experience the reality of the perspective in which I occupy directly for myself, and (3) it seems rather intuitive to then conclude that all possible descriptions of reality from all possible perspectives also correspond to an actual reality from that perspective (i.e. each possibly description of reality from any possible perspective also has a corresponding "what it is like to be" in that perspective).
Rejecting #3 seems to fall into solipsism since you would only be left with the reality from your own perspective, and descriptions of other perspectives would not have a corresponding reality to those descriptions. Accepting #3 would assign reality to all possible perspectives, and thus there would no reason to treat mammals with brains as anything special requiring a special explanation with some special "consciousness" property, since the physical sciences allows us to describe reality even from the perspective of inanimate objects like rocks.
It is clear you need an additional fourth premise to insist that mammalian brains do something special that requires a special explanation, and I do not see what that fourth premise could possibly be.
As I said, experience is just the reality of a particular frame of reference. To ask why there is a reality to it, you are just asking why there is a reality rather than no reality, i.e. not much different than a "why is there something rather than nothing" question. It cannot be meaningfully answered. You can explain why something in reality exists, but then whatever explanation you give will still deal with aspects of reality, which you can then just ask why those aspects exist, and repeat this as an infinite regress, constantly asking "why" to every question. At some point, you just have to respond, it is what it is. Reality as a whole cannot have an explanation. It just is. You just have to accept reality is as a start point or you will never get anywhere.
Experience is not something created by brains. Experience is, again, just reality as it exists from a particular perspective. Brains play a role in what we experience, but so does everything else as well. Every object we posit to exist, including our brains, play some predictive role in allowing us to explain and forecast experiential reality. But none of these objects create reality, as if reality is something that is "given rise to." Reality just is. We can identify objects within reality and use those objects to explain and forecast reality, but none of them can possibly play any sort of creative role in giving rise to reality itself. Logically, it makes no sense, as it is reality which grants objects the quality of being by definition.
I am not a fan of the interchanging of "experience" with "feeling" as you are using, kind of like when you also interchange it with "consciousness," because these words like "feeling" and "consciousness" clearly have human-centric implications to them. This is obvious if we apply these different words to inanimate objects. It clearly has rather mystical implications to say things like a rock can "feel" or it has "consciousness." However, to say the rock can have an experience is part of everyday language, i.e. "the rock is experiencing erosion in the rain," or "the rock is experiencing fluctuations in temperature." The word "experience" just means to undergo a real event, so this kind of language is rather natural, while assigning "feeling" or "consciousness" to a rock seems to anthropomorphize it too much.