>Modern Egyptians have almost no dna connection to ancient Egyptians.

That's just false. Modern Egyptians are quite clearly and cleanly descended from Bronze Age Egyptians. There's quite a bit of African and Arabic input, but not to the point of the population being unrecognizable.

It's nearly impossible to replace a settled, agricultural population with immigration. There needs to be active, systemic policy of ethnic purge.

It would be a fair point to say they have little to no cultural connection to pre-Islamic Egypt, but bringing genetic into the mix is specious.