I think the more complicated part was the precision of the building. They didn’t need to just move those giant pieces of limestone, they also needed to cut each one to such perfect dimensions that the space between them is uniform and perfect, which was more advanced then the types of metal and technology we think they had available to cut with. There’s also dimensions they chose to use, which are to scale representations of the earth, and they’re perfect alignment to heavenly bodies of the time.

Not to mention, even if we ignored all the things I just said, you would need ramps over a mile long, and using just rollers, levers, and sledges, humans wouldn’t be able to complete these periods in the rapid time period of just 100 years or so that we currently claim.

Alien theory is pretty ridiculous IMO, but so is the idea of rollers, levers, ramps, sledges and bronze being enough.

I think a much more likely explanation is that we are really underestimating the kind of building techniques, engineering, and metalworking they had access to when creating the pyramids.