... but you still need thousands of
people to build a complex like Giza, and i havent seen any evidence of a pre existing society with those requirements needed to do a Giza , so it looks like the 4th Dynasty time is the correct time for G1's inception.
Uhh, what?? Have you not heard of Gobekli Tepe? It's practially right around the corner from Giza. The site is so huge most of it will never be excavated. Megalithic stones, beautiful skilled artistry, high relief sculpture, profound knowledge and understanding of astronomy, geometry, statics. Demonstrable ability to quarry, transport, balance and place megalithic stones of enormous weight with precision.
This does not qualify in your mind as a culture that could construct the larger monuments at Giza?
If you don't like that one, there's evidence of another candidate culture in Indonesia. Gunung Padang has returned dates as far back as 25,000 years ago in its deepest layers(which also appear to have the largest megalithic blocks, as usual). The Sulawesi valley nearby is liberally sprinkled with strange, ancient monolithic sculptures, huddled in rice fields, skulking beneath the dark waters of jungle swamps, looming in the shadows beneath the trees. There are numerous gigantic stone vases scattered about as well, complete with fitted lids that have high relief feline and lizard sculptures on top. And those containers look identical to the stone "jars" in Laos, Cambodia, of which there are thousands, scattered across the plains (and surrounded by minefields, unfortunately).
The feline and lizard high relief sculptures on the lids of the jars look extraordinarily similar to high relief sculptures found on the cyclopean blocks of the Chullpa towers in Peru and Bolivia and on the huge pillowed megaliths in the jagged walls of Sacsayhuaman above Cuzco. There are even a few lizard reliefs found on blocks in cyclopean, heterogeneous, dry laid masonry platform walls on Easter Island. And the Moai of Easter Island are all shown with their arms to the sides, curving forward with their hands placed just above the belt, which has a curious 'H' shaped buckle, and their hands have distinctively long, tapering fingers. This is weirdly similar to the highly stylized anthropomorphic T pillars at the center of each ring in Gobekli Tepe, which have the same 'H' shaped belt buckle, same arm position, and same odd, long, narrow, tapering fingers.... and we're back where we started.
This is very good evidence of a global, globetrotting, advanced, megalithic genius culture in deep, deep antiquity. The height of their ascendance was somewhere way back in the ice age; very little evidence of them remains aside from their megalithic constructions. The ELE at the Pleistocene/Holocene boundary erased them almost entirely.