Assertions about the ethnicity of Ancient Egyptians have been useful for people who had political / social agenda and wanted the ancient Egyptians to be black, and for people who wanted them to be white.
For those who wanted them to be black, there was feeling of pride in one of the most advanced ancient cultures, having been a product of black people. For white supremacists and generally Euro-centric folks, claims of the ancient Egptians' supposed whiteness fed into their assertions that great civilizations are always a result of white intelligence and other superior traits. Of course, this leaves out the ancient cultures of China, India, and independent development of advanced cultures in the Americas, but who's counting those?
DNA analysis has been complicated by processes that degrade DNA, but some DNA from some mummies has been analyzed. The scientists were meticulous about avoiding contamination by modern human DNA. The oldest mummy was from 1388 BCE, the newest was from 426 CE. Egyptian culture is millenia older than that, but this study was a start.
The result? "ancient Egyptians were most closely related to the peoples of the Near East, particularly from the Levant. This is the Eastern Mediterranean which today includes the countries of Turkey, Iraq, Israel, Jordan, Syria, and Lebanon."
In other words, ancient Egyptians were not sub Saharan African, and they were certainly not Nordic either. They were Middle Eastern.
Of course, there are considerations that affect this analysis. Are mummies typical for all ancient Egyptians, or are they part of an elite class? In some periods of some empires, Chinese, I think Indian, Turkish / Ottoman, and I think Aztec and Inca, the ruling class was not the same ethnicity as the rest of the empire. The ruling class of Egypt was famous for incest, so what was that effect? The historical origin of a unified Egyptian Kingdom dates back to 3150 BC. So there were nearly 2000 years, roughly, before the origin of the unified kingdom, and the oldest of these mummies - as long as the time between Julius Ceasar, and our own time. With migrations, invasions, genocides, epidemics, enslavement, overthrow and establishment of new ruling dynasties, conquest, sexual adventurism, rape and pillage, one could still claim that the "original" Egyptian empire, the one from which the others sprang, was not the same ethnicity as the empire 2 or 3 millenia later. And that point seems valid.
But this is a start. The good thing about science, is it is fairly independent, usually, from political/social claims like "the black / white origins of the Egyptian Empire prove that civilization and culture originated from black / white people, who are therefore superior to white / black people".
So it looks like the people of Ancient Egypt, as far as we can tell so far, were Middle Eastern. Ancient Chinese civilization consisted of Ancient Chinese, ancient MesoAmericans were Olmec and Toltec, in other words, mesoAmericans. Which means that civilization arose independently from people of various races and ethnicities, and no one can claim it all derives from a particular tribe.
If one would like to see what ancient Egyptians looked like l, go to Egypt. There is no evidence that there has been any major migrations or in flux of other ethnicity in the last 4000 years. Sure there was Nubian warriors that were used as mercenaries, but that made no major influence in the overall population demographics.
From the reports, modern Egypt has more subSaharan African DNA than ancient Egypt did. That was due to Arab slave trade. The world is a wild place, with all sorts of movements and mixing!