The thing is, the Sphinx sits on the edge of the Sahara Desert and the region has been quite arid for the last 5000 years. Furthermore, various structures securely dated to the Old Kingdom show only erosion that was caused by wind and sand (very distinct from the water erosion). To make a long story short, I came to the conclusion that the oldest portions of the Great Sphinx, what I refer to as the core-body, must date back to an earlier period (at least 5000 BCE, and my latest research now points to the end of the last ice age, circa 10,000 BCE), a time when the climate was very different and included more rain.
https://www.robertschoch.com/sphinx.html