I have had ego death/out of body experiences on high doses of various hallucinogens. The brain still has electrical activity but the sensory experience is unfathomable.
In my experience it felt like what I could only imagine real death is like. Intense feelings of terror/fear, impending doom, anguish, pain, regret, sadness and despair for what it will do to family and friends that are left behind in the wake of your death. All of these thoughts, emotions, beliefs that have become a part of your personality and the construct of your consciousness, you're very existence who you believe yourself to be as a person it all flashes before you, and the more you fight it and cling to life the harder and more difficult the experience is (I imagine this is much like how it is for real death, especially if you know that death is certain and near, save for sudden death or unconscious death)
However, all these things come to a point, a breakthrough, and dissolve into nothingness. Boom
Blasted out of body into an ethereal space where there is no pain, no fear, oneness with the universe. All is connected. There is no sense of self, but there is a "sense" of connectedness, an enveloping energy of some sort.
But it could all just be the effects of the hallucinogenic substances. Almost impossible to say with 100% certainty
I have had numerous out of body experiences, some where I have interacted with deities, God like beings, aliens, Egyptian God's, trans/interdimensional beings made of light, demonic/evil spirits...
To answer your question however, I don't believe I am qualified for that. To me it seems highly unlikely that any of those scenarios occur.
Most likely we just cease to exist as we are and go back to the void from whence we came, or we reincarnate, as energy is not created nor destroyed, only transformed.
Reincarnation could be seen as a perpetual hell I suppose, but your old memories will most likely be left behind with your previous life if that is the case however there are instances in which people are born with memories from supposed past lives.
There are many mysteries about life and death and the nature of existence. To which humankind has many more questions than it does answers.
I'm still searching for answers myself. Part of me desperately hopes there is a God, a heaven, an afterlife where when I die I will get to be with my beloved.
But to believe in heaven would I also have to believe in hell? In some ways I do. My life is a nightmarish hell I cannot escape from only by the hands of death shall I be delivered from my suffering.
Something of interest that has only led to more questions rather than answers is this interesting piece of history,
en.m.wikipedia.org
In medieval Japan, this tradition developed a process for sokushinbutsu, which a monk completed over about 3,000 days.[10] It involved a strict diet called mokujiki (literally, 'eating a tree').[12][11] The diet abstained from any cereals, and relied on pine needles, resins and seeds found in the mountains, which would eliminate all fat in the body.[12][5] Increasing rates of fasting and meditation would lead to starvation. The monks would slowly reduce then stop liquid intake, thus dehydrating the body and shrinking all organs.[12] The monks would die in a state of jhana (meditation) while chanting the nenbutsu (a mantra about Buddha), and their body would become naturally preserved as a mummy with skin and teeth intact without decay and without the need of any artificial preservatives.[12][5] Many Buddhist sokushinbutsu mummies have been found in northern Japan and estimated to be centuries old, while texts suggest that hundreds of these cases are buried in the stupas and mountains of Japan.[11] These mummies have been revered and venerated by the laypeople of Buddhism.[11]
One of the altars in the Honmyō-ji temple of Yamagata prefecture continues to preserve one of the oldest mummies—that of the sokushinbutsu ascetic named Honmyōkai.[13] This process of self-mummification was mainly practiced in Yamagata in Northern Japan between the 11th and 19th century, by members of the Japanese Vajrayana school of Buddhism called Shingon ("True Word"). The practitioners of sokushinbutsu did not view this practice as an act of suicide, but rather as a form of further enlightenment.[14]
en.m.wikipedia.org
Rebirth in
Buddhism refers to the teaching that the actions of a sentient being lead to a new existence after death, in an endless cycle called
saṃsāra.
[1][2] This cycle is considered to be
dukkha, unsatisfactory and painful. The cycle stops only if
moksha (liberation) is achieved by
insight and the
extinguishing of craving.
[3][4] Rebirth is one of the foundational doctrines of Buddhism, along with
karma,
Nirvana and liberation.
[1][3][5] Rebirth was however less relevant among early Buddhist teachings, which also mentioned the beliefs in an
afterlife,
ancestor worship, and related rites. The concept varies among different Buddhist traditions.
[6][page needed][7][8]
The rebirth doctrine, sometimes referred to as
reincarnation or
transmigration, asserts that rebirth takes place in one of the
six realms of samsara, the realms of gods, demi-gods, humans, the animal realm, the ghost realm and hell realms.
[4][9][note 1] Rebirth, as stated by various Buddhist traditions, is determined by karma, with good realms favored by
kushala karma (good or skillful karma), while a rebirth in evil realms is a consequence of
akushala karma (bad karma).
[4] While nirvana is the ultimate goal of Buddhist teaching, much of traditional Buddhist practice has been centered on gaining
merit and merit transfer, whereby one gains rebirth in the good realms and avoids rebirth in the evil realms.
[4][11][12][note 2]
The rebirth doctrine has been a subject of scholarly studies within Buddhism since ancient times, particularly in reconciling the rebirth doctrine with its anti-essentialist
anatman (not-self) doctrine.
[4][3][13] The various Buddhist traditions throughout history have disagreed on what it is in a person that is reborn, as well as how quickly the rebirth occurs after each death.
[4][12]
Some Buddhist traditions assert that
vijñana (consciousness), though constantly changing, exists as a continuum or stream (
santana) and is what undergoes rebirth.
[4][14][15] Some traditions like
Theravada assert that rebirth occurs immediately and that no "thing" (not even consciousness) moves across lives to be reborn (though there is a causal link, like when a seal is imprinted on wax). Other Buddhist traditions such as Tibetan Buddhism posit an
interim existence (
bardo) between death and rebirth, which may last as many as 49 days. This belief drives Tibetan funerary rituals.
[4][16] A now defunct Buddhist tradition called
Pudgalavada asserted there was an inexpressible personal entity (
pudgala) which migrates from one life to another.
[4]
I do apologize for this long response, however I hope it helps with the questions and feelings you are experiencing.