This does it for me. I keep reading more and more articles which debunk the theory of carved and dressed stones as buildin blocks for the pyramids.
No reason to dispute this theory. It answers all the questions that rule out the previous theories.
And as far as the lost technology of cement, we have ample evidence that it can happen. The Romans are acknowledged to have used cememnt extensively in their building projects—bit the technology was lost again until the rediscovery in the 1800s with Portland cement.
Roman concrete was different, and the exact method is still under discussion, but it differed from the various Egyptian methods and materials — however, all are/were analogous to each other.