Skilled paid stonemasons were required to build the tight fitting surface stones of this one, so some of the laborers were definitely not slaves, howeveri believe you're correct I doubt the sled drag team was salary.
They actually don't really know how they did it, there are the voices that say ramps would've been so enormous that they wouldn't have been practical in a realistic sense:
https://www.cheops-pyramide.ch/khufu-pyramid/pyramid-theories.html
There are supporters of the lever theory, even several different methods depending on the progress of the construction:
https://en.wikipedia.org/wiki/Egyptian_pyramid_construction_techniques?wprov=sfla1
But as I understand it as a complete layman ( my only qualification would be that my ex girlfriend was an egyptoligist) that the more they examine it, the more voices raise against a solely ramp method. The old egyptian were highly pragmatic & efficient, so I've heard, and the stones were gigantic, sand ramps are at least partly unpredictable & sand is not the stiffest construction material - sooo, I don't really know & as far as I know, science doesn't either, at least no exhaustive answer. So far
Wet sand, along with pulleys and lots and lots of man power, and using the Nile to float stones from upstream to the building site. More complicated than that, but yeah.