Sounds like a franchise operation.
Serious comment: looking at the picture, it looks like it was a rubble core, with exterior blocks facing it. I recall we were pinged to a recent article by an engineer who claimed this was how the larger ones were built.
In any case, I'm glad I didn't have to help build it: I prefer carpentry to masonry, having done both for a living at various times.
The claim that the Great Pyramid has a rubble core is known to be false, and was known to be false before he made that claim. IOW, I wouldn’t put too much stock in what he said. The earlier step pyramids were built of mud brick, rather than stone, and it’s surprising they haven’t deteriorated and “sagged” more than they have.