Ogy:

Proper motion is an angular measure of star distance and direction over time and their measures are next to negligible/zero over the short span of 5,000 years, therefore the only issue at hand for star location/viewing at the advent of Giza would be Earth’s preseccional cycle characteristics.
What was the exact location in the heavens that Earth’s north pole pointed to 5,000 years ago?
I have used several “sophisticated” programs only to discover that all have weakness of data input resulting in variable outputs. I elected to create my own program dedicated to the major visible “northerns” and believe me…nobody can declare a measure to within 1year of accuracy as factual.
What must be determined in the calculations is the exact number of years for Earth to complete this cycle…presently unknown.
Also to determine if the imaginary precessional circle around the N.E.P. is constant or of if it contains a sinusoidal oscillation of angular deflection as some scholars have theorized…presently unknown
However, not knowing the exact characteristics only effects the outcome by several years. But, to assist us, I believe the designers of this site encoded several examples of a 23.47 degrees measure in the GP’s design, and if this relates to Earth's tilt then it has only changed slightly since the Giza site was constructed (present angular measure is 23.45).

Best.
Clive