One of the frustrating things about these claims, generally, is that they take an extraordinarily skeptical view of what ancient people could do, but then become amazingly gullible , believing without any actual physical evidence, that space aliens and/or time travelers or lost civilizations had to be involved.

We have a lot of existing evidence for the Egyptians building whole tomb complexes, as an outgrowth of their religious system, for a very long time. The Giza pyramids are simply big , famous leftover examples from that ( you can read about that in the FAQ section, here). If the Egyptians didn't have the technology to build the pyramids and all their many tombs and tomb complexes, and they got someone else to build them instead (for thousands of years) who, then would that be? Where are they? If someone would like to claim they were built by someone else, we should expect them to show an equal mount of real stuff as evidence of that mysterious constructive force. Ask them to show us actual things, like, alien documents, landing pads, pictures and statues of aliens, a broken bit from an alien pneumatic drill...

But, because we don't have physical evidence otherwise, perhaps we can just claim that the Egyptians indeed had the technology to build the pyramids. Because the pyramids got built.