If a slave is granted accommodation and food by his master, is it functionally different from a worker in a country with no social security, whose wage does not cover both food and accommodation?

If we're talking about the pyramids the amount of quality building material in there was not sourced from slavery. Egyptian used slavery in farming and in army and logistic matters, but these heavenly buildings were all pretty important. What we do know is that salvery was also an outcome of tye conquest of other areas and cultures, so they forced them into what was considered egyptian culture at the time. And it's a damn long time span of many hundreds of years. We have so much documentation from the egpyptian kingdom. There are things that are more mysterious than the pyramids to me, temples and little oddities like the Osireion.