The whole concept of “ancient architects” is interesting. How were they trained? Were there schools of architecture? Or was it purely apprentice / master training?
Mathematics and structural engineering were not very evolved at the time - how were they used? What did the architects use for drafting? It’s not like you could go to the local store and buy vellum, drafting tools, pencils and lead? How did they get something as simple as a straight-edge? Paper was in its infancy; did they use parchment or papyrus? What happened to all the architects’ drawings and plans? Were the drawings reproduced for the builders to use? Did the architects make a lot of conceptual sketches for their clients (probably the king)?
There were no real standards of measure. What units did they use? How did they measure long distances?
How did the masons lay out straight lines? Did they use taut string like is used today? How was small gauge string made in long lengths for such distances?
Have these and many other questions been explored?
Spoiler alert, they did not use drawings.
Al Ula is positively modern compared to the pyramids.
Hegra is dated to 300 BC circa. The pyramids are 2000 years older.
For straight lines the pyramid builder used a simple string and holder technique. And they had standardised units of measure.