Why are most Christian beliefs match with the spiritual practices of the Ancient Egypt?

I'll quote the perfunctory Chestertionian reply to the all religions are the same and Christianity is a religion therefore its the same argument.

I take a third case; the strangest of all, because it involves the one real objection to the faith. The one real objection to the Christian religion is simply that it is one religion. The world is a big place, full of very different kinds of people. Christianity (it may reasonably be said) is one thing confined to one kind of people; it began in Palestine, it has practically stopped with Europe. I was duly impressed with this argument in my youth, and I was much drawn towards the doctrine often preached in Ethical Societies—I mean the doctrine that there is one great unconscious church of all humanity founded on the omnipresence of the human conscience. Creeds, it was said, divided men; but at least morals united them. The soul might seek the strangest and most remote lands and ages and still find essential ethical common sense. It might find Confucius under Eastern trees, and he would be writing "Thou shalt not steal." It might decipher the darkest hieroglyphic on the most primeval desert, and the meaning when deciphered would be "Little boys should tell the truth." I believed this doctrine of the brotherhood of all men in the possession of a moral sense, and I believe it still—with other things. And I was thoroughly annoyed with Christianity for suggesting (as I supposed) that whole ages and empires of men had utterly escaped this light of justice and reason. But then I found an astonishing thing. I found that the very people who said that mankind was one church from Plato to Emerson were the very people who said that morality had changed altogether, and that what was right in one age was wrong in another. If I asked, say, for an altar, I was told that we needed none, for men our brothers gave us clear oracles and one creed in their universal customs and ideals. But if I mildly pointed out that one of men's universal customs was to have an altar, then my agnostic teachers turned clean round and told me that men had always been in darkness and the superstitions of savages. I found it was their daily taunt against Christianity that it was the light of one people and had left all others to die in the dark. But I also found that it was their special boast for themselves that science and progress were the discovery of one people, and that all other peoples had died in the dark. Their chief insult to Christianity was actually their chief compliment to themselves, and there seemed to be a strange unfairness about all their relative insistence on the two things. When considering some pagan or agnostic, we were to remember that all men had one religion; when considering some mystic or spiritualist, we were only to consider what absurd religions some men had. We could trust the ethics of Epictetus, because ethics had never changed. We must not trust the ethics of Bossuet, because ethics had changed. They changed in two hundred years, but not in two thousand

GK Chesterton. Orthodoxy

Basically, you have two things. Christianity and everything else. Christianity has altars and priests and sacrifices and oils and water and blood and bread and wine and incense. Ancient Egypt has all these same symbols and practices. That doesn't make us the same, it might make us both human, it might even be that there is something natural on the way most of humanity communicates with the divine.

But, Christianity differs in ethics from ancient Egypt and you can see this in the way that Europe ended the Servile State in the middle ages and re-invented it after the reformation. Egypt tends toward slavery, Christianity tends toward freedom. When you look at sacrifice, in pagan religions, the religious authority sacrificed the innocent. In Christianity, the greatest good is to sacrifice yourself.