Recently a group finished a stone block of the size in the Egyptian pyramids in just a few days.

Another group hauled a Stonehenge sized block of stone from area the stones came from to the site of Stonehenge in about two weeks.

Estimate is that, using existing tools of the time, 100 stonemasons could have done the Sphinx in about five years.

And we have medieval and classical buildings in Europe where the building methods are fully known and there were no flying saucers or other magical methods.