Early history is fascinating!
Regarding the timing of the flood and ancient Egypt, my personal belief is that the old kingdom of Egypt is post flood. I don't believe the pyramids could have survived the flood. The Bible says the per flood world was erased.
Many secular archaeologists stretch their timeline. Remember, they have millions and billions of years that they are trying to account for. So, they miss it by a thousand years or so. What's that to them? I believe many of them stretch the old kingdom to earlier than it actually was. But that's just my opinion.
The timeline on page 50 was about the best I could do from *many* trusted sources. None of them agree entirely, so you are left trying to sort it out for yourself based on much reading of good sources.
I would love to see timelines from all of you, especially as to how you handle the 2500 BC to 1800 BC era, a fascinating period!