A disjointed argument against near-death experience as a source of facts about the after-life (for want of a better title)

So some people who have died medically and been resuscitated claim there is nothing after death.
“We” agree that they died medically, but the fact that they are “here” to tell about it means they did not die finally.
And if they did not die finally, how can we then be sure of where they were during that period when to all intents and purposes they were dead?
People who have a concussion or lose consciousness may wake up and not remember a thing. We do not know where their minds or souls were during that period. We have come up with all sorts of explanation – purgatory; some tunnel with a light at the end; etc. But it is all just conjecture.
I understand when people are “put under” (general anesthesia) some have a near-death experience.
I had mine. I was in some sort of a really small box, that was in a box, within a box, to no end. The boxes were shiny and dark at the same time. How I came to know the boxes were stacked like a Matryoshka doll I could not tell for sure. But it was as if I was trapped inside but able to see the whole thing from outside at the same time. But no matter how hard I struggled I could not get out.
There was some sort of very regular booming sound, like a thunder clap. At some point I gave up struggling, I thought maybe this was hell and I was dead and my sins had found me out. I thought this was no way to spend eternity. I despaired. But then I woke up once the anesthetics wore off.
Now some people will say those who medically died and got resuscitated is the closest thing we have to dying fully. That is all fine and good. But being close is not the same as being exact or the real thing. Death is final. From my limited recollection of calculus math, no one knows what the biggest number is or we accept it is infinite or infinitely big.
For all intent and purposes, we say “sufficiently big” is an approximation of infinity. But who knows what would happen if we could indeed discover that biggest number? Would our minds implode? If we could build a computer that could handle it, would the computer become self-aware – a sentient being? Or since only God is truly infinite, would such a number be the number of God? If our mind could grasp it, would we achieve enlightenment and be as God or gods?
Again, all these is just conjecture. People who “died” and “returned” cannot be our source of truth about life after death. Obviously as a believer myself, this excludes Jesus.

5/27/2019 (1:44AM)