I won't deny, I'd love to see a major canal-building Egypt. (I argued an entire TL premise on this, using the Kushite Period). Egypt has the food, and arguably the manpower to build a "Suez Canal", but it'd take a huge amount of time to do.
But lets say that we have a major canal-building effort for this Kushite Egypt (Who were Pharaohs). You essentially now have a moat that defends Egypt, that can be fortified and readily supplied by ship, expanded up on later years, etc.
In theory, if the 25th Dynasty can achieve their canal building process (no small feat), you have fortified artificial waterways from deep in modern Sudan and across the site of Suez, that can be reinforced by sea rapidly.
Suddenly Egypt is much. MUCH harder to invade if organised. It also makes unification harder, because if someone can hold those canals, they control trade with little more than a few garrisons and enough gold and food to pay them.
But if we stick with just the Suez, it can be expanded, new canals dug, with the debris shipped out from the older canal(s). You'd probably have two large, and old, cities at either end, and a significant body of people with engineering know-how being produced all the time.
It would cost a fortune to build, but post-Bronze Age, it is a worthwhile endeavour if you also make it a security feature. It could even mean a native Egyptian or Kushite dynasty maintains control rather than Persia, or Macedon.