Ancient pyramids Why build them?

HYPOTHESES...

1. Once it was considered - to protect against floods in the flat terrain.
2. We also thought that this is a giant solar calendar clock.
3. To protect against earthquakes (the pyramids of their mass extinguish the soil).
4. It is also possible that the ancients wanted to perpetuate the memory of themselves or some long-standing event, and for this they chose the shape of the structure at the same time and the most stable, and so that the structures, even with their strong destruction, could not be confused with mountains of natural origin.
5. Pyramids are like graves for their pharaohs, although they were built during the Atlantean times. Their gigantic dimensions are due to the fact that the Atlanteans themselves were huge.
6. The complex of pyramids is something like the memorial of the deceased Atlantis, which stores all the surviving state documents of the disappeared continent, the bodies of immigrants from Atlantis, musical instruments, banners, decorations of temple altars, seals, fabrics, medicines, gold.
7. Pyramids are a means to gain eternity for the soul. How this can happen - no one really can explain, but many intuitively feel it.
8. The pyramids could be used by the Atlanteans to "throw the dead" of their contemporaries into the Future.
9. Pyramids are something like energy sources.
   There are other, even more extravagant hypotheses. And even more unproven.
   And how else if the ancients did not leave instructions?! But perhaps the mystery is quite different - it is that the pyramidal form from time immemorial attracted man to its completeness. Anyway, the pyramids built, built and, probably, will be built.

...unconfirmed?!