This subject is a controversial one among contemporary Egyptians as well. Some among the upper classes want to identify more with Arabs, other Mediterraneans, or perhaps even Europeans. They deny [yes, "denial" is a river in Egypt ] their location has any connection to sub-Sarahan Africa.
In fact, there have been requests by scientists based elsewhere to do genetic analyses of samples from mummies. There has never been permission granted by Egyptian authorities for such studies. The reason given is that the process of mummification has contaminated the samples. But that's no more true than saying my tattoos have altered my genetics. Perhaps they fear such evidence will mean a firm connection to the rest of Africa. There may also be a few people who fear it won't.
But look at any street scene in Cairo and especially of anywhere in upper (southern) Egypt. Egyptians show a wide variation. Including what is thought of by North Americans and Europeans as typical for central or western Africans. So do portraits from the ancient world governed by the the Alexandrian Greek Egyptians. As does the art when it depicted ordinary life in archaic times.
Formal requirements of the various dynasties or of complex spiritual functions means this type of art was done in a specific manner. With conventions having to do with religious symbolism that depict people as red, white or black, but not because that was actual skin color. Notice for example how women are colored in contrast to men in formal symbolic art.
Look also at the eastern Africans of Eritrea, Ethiopia, Somalia, and some of the people in northern Kenya and Uganda. Slim body builds are predominant, as are long faces and straight noses. Their skin color varies quite a bit. Yet no one denies they are Africans. These features seem to be quite similar to those of the archaic (ancient) Egyptians.
I recommend reading Black Genesis by Robert Bauval amd Thomas Brophy. Bauval is an engineer of Belgian descent who was born and raised in Egypt. He is also connected to the group which presented some solid evidence based on geology that the Sphinx shows erosion from water, not wind. Which would make it far older than the dates given by most mainstream archeologists.
The book is about Nabta Playa and how prehistoric Black Africans once living there probably are among the foundational people of the later Egyptian culture. The authors do not claim to have explained everything, but their evidence for a connection between Egypt and the rest of Africa is compelling.
As for conjecture, I also think Atlantis a possibility. But I don't confuse that with really solid scientific evidence. Read Colin Wilson or better yet, Rand Flem-Auth and their books that make the case for Atlantis being in Antarctica. There are old maps that show the coast of that continent without ice! There are legends that the Atlanteans were snake-eyed, which is a way to say epicanthan folds like East Asian people. But the Bushmen and related people in southern Africa also have them. These people have had a continuous culture for likely more than 10, 000 years. What if they were also the ancestors of the Atlanteans?
Behind all of these battle over skin color of ancient civilizations is the once common assumption that all superior humans were light skinned. A little over a century ago, even the learned at places like Harvard held such beliefs. Which served to support colonialization. Truth is, western European people were civilized rather late. The cultures of Africa (look up Meroe and Ashanti, for example) were way sooner.
And even if it were at all true that somehow there is evidence white people are "better," what would that have to do with the average person? We working people and peasants, 90% of the population, didn't even have much schooling or literacy until about 150 years ago. In addition, there are now millions of Africans and Black Americans with PhDs or whatever, which would make them superior to almost all of us white people.
This stuff about Egypt is the same old long discredited silliness projected back in time. But just in time for the next set of American elections. Maybe no coincidence considering that the current US president is half Kenyan. Hatred and fear are always useful for those who will do anything for power.