Shaving was hard before the invention of metal knives.
I regret I do not now recall the name of the book but I read in one book about Ancient Egypt, which had pictures to prove it, that in very early times, I think before 3,000 BC, when pre-literate Ancient Egyptians scratched or coloured pictures, as they sometimes did, they showed their men, who were not naturally as hairy as other races, with unimpressive small beards, which are probably all that grew naturally for them.
From the Bronze Age, which roughly coincided with the appearance of literacy, Egyptian men were portrayed clean shaven. Men of some foreign nations, often also distinguished by their style of dress and other features, may be shown with beards, sometimes probably to conform to a stereotype to identify the picture as being of a Syrian or whatever.
It seems the Ancient Egyptians therefore adopted shaving around 5,000 years ago, almost as soon as it was easily possible once they had sharp enough metal implements. Thereafter, they stayed clean-shaven pretty well as long as their civilization lasted, so for the next 3 thousand years. That would be remarkable for other societies but less so for the Ancient Egyptians, who once they found a style that suited them tended to stay with it for an amazingly long time.
A sketch survives from Deir el-Medina, the village of the workers on the royal tombs in the Valley of the Kings in the New Kingdom (c 1550 - 1080 BC), probably made by one of the workmen in his spare time, of a man wearing the an Egyptian Royal Crown, looking slightly overdue for a shave, with bristles ('five O'clock shadow' we may now call it) showing on his chin and cheeks.
In other words one of the workmen was probably being slightly naughty in showing the King caught not looking at his best, and differently from the formal and invariably respectful portraits that the painters and sculptors of the Royal tombs had to produce in their day-jobs.