I'm pretty convinced ancient Egyptians stumbled across the Pyramid culture and squatted on their stuff, and then claimed it as their own. Even within parts of their own history ancient Egyptians said they weren't there first, and they documented a huge chunk of their own pre-history in the Turin King List, which dates occupation of Egypt back 36,000 years (or so).

I think modern, post-Rosetta stone, Egyptians have tied a lot of their self-identity to being "THE FIRST" civilization. This idea is fundamental to how they view themselves, and they have even found ways to reconcile this belief within their views of Islam. It's super important to Egyptians that they were first, because frankly they haven't offered anything else of value to the planet since Rome stopped giving a shit about their wheat crops.

So, I believe shit-bags like Zawi Hawas and other like minded individuals in Egyptology have been actively suppressing information which may indicate that another older civilization, who were distinctly not-Egyptian, built most of the massive monuments in the Nile Valley.

If you look at many of the monuments, hieroglyphs appear to either be engraved in a manner way more shitty than the monument was built, or they simply added a plaster outer casing to the monument and added their writing on top.

Egyptians weren't afraid to erase elements of their own history, as we have seen with how they treated Akhenaten/Amenhotep and Nefertiti.

To go a little further with this idea, I'm also convinced that any culture that might have built the pyramids likely also inhabited a huge chunk of what is now the Sahara desert. Post flood, the region was lush with wildlife and greenery and remained this way from about 8,500 BC to 5,500 BC. Around 4,000 BC the Egyptians document their first Dynastic pharos.

Personally, I think 50'-100' below the sand across the entire Sahara region we might find evidence of a super-culture who might have lived on the banks and rivers of what is now called Mega Lake Chad. I think it might have been these people who developed quickly following the 9,500 BC flood event and spread across North Africa, eventually building settlements in what is modern day Egypt and any evidence Egyptians may have found has been quickly squirreled away.

On the upside, if I am right, there is a lot of desert to be excavated that isn't under control of the Department of Egyptian Antiquities.

Oh... and then there is Doggerland. But that's another long winded post I don't feel like writing about right now, lol.

TLDR; I think Egyptians are squatters in mega structures built by a culture who previously lived in an area of the Sahara now covered by sand.