People are fascinated by what happens after death. At any given time the booksellers’ shelves have one to several best sellers about someone who claims to have died, gone to heaven (rarely hell) and returned to tell about it. Ignoring that most of these books do not agree on particulars, people want to know what will happen after we die. Nor is it a new phenomenon. After all, the whole purpose of monumental burial (think the pyramids, or any cemetery) is to prepare or preserve a body for the afterlife. Even the ancient Egyptians had their books of the dead, which were guidebooks through the underworld written by men who had never been there. Strangely, with all the books about what happens after death on the shelves, few people consult the Bible on the subject. Well, perhaps not strangely, since the Bible is essentially silent about the matter, and what it does say contradicts most of the books on the shelves.
Throughout the Old Testament there is extremely little about what happens after death. The Psalms, for instance, give the impression that once a person is dead they go into the grave and that is the end of the matter. And yet the Jewish people had a concept of the resurrection of the dead.
Actually, even two millennia ago that was a major point of contention for the Jews. The Sadducees denied a resurrection; the Pharisees advocated for it. It even got to the point that they practically came to blows over the issue. (Acts 23:6-10) The Sadducees, accurately, argued that the scriptures say nothing about life after death. The Pharisees argued it was true nevertheless.
Jesus and his apostles maintained the existence of the resurrection, and therefore of something following death. In 1 Corinthians 15 Paul argues that the resurrection of Jesus proves a universal resurrection, and gives one of the few New Testament descriptions of it.
Today we have all the books describing people dying and going to heaven and coming back to tell of it. All of them are in contradiction with Paul, who described one who had gone to heaven and was forbidden to speak of what he saw or heard there. (2 Cor 12:1-4) Although most attribute this experience to a death and return from the dead there is nothing in the passage to indicate that the person died. It does indicate, though, that he could not describe what he saw during the experience.
There is much argument today particularly about what happens between death and the final resurrection and judgement. Some, based on 2 Corinthians 12 and the story of the rich man and Lazarus in Luke 16, propose an intermediate waiting place where there is a separation of the saved and the non-saved, but in which they are all conscious and awaiting the final resurrection. Others argue that the soul loses all consciousness until the final resurrection of all the dead. The bulk of scriptures about the end of this world seem to indicate that the dead will be raised from the earth at that time. This would seem to support the latter contention, but it is possible that everyone will come back to earth from the proposed intermediate place, and then be raised bodily (although in a new body). Both sides use, and abuse, scriptures to support their contentions. Neither has any real experience with the matter, nor does it seem to make any real difference which is right.
Ultimately, the final judgement will be based on whether people followed Jesus or not. That is a decision that can only be made in this life. Therefore, whether we sleep or remain conscious or even cease to exist for a while is irrelevant. In eternity, that is the space between a period and the beginning of the next sentence. Asleep or awake, we may not even notice the time difference.