How Evolution changed humans’ appearance

No - Homo erectus is very much on our line of the family tree. The last common ancestor of humans and chimpanzees is believed to have lived about 5-6 million years ago, based around evidence from mutation rates. H. erectus lies on our side of the split, and appears in the fossil record from about 1.8 million years ago - so it's much closer to us than a chimpanzee.

The species from around the time of the human/chimp split are Orrorin tugenensis and Sahelanthropus tchadensis. They're only known from sketchy remains, and it's controversial whether they should be treated as nearer to humans or chimps, or off on their own seperate branches.

I think your ideas are a but outdated here. The magical date of 50,000 years for the sudden emergence of a modern, cultural package is the hangover of Eurocentric palaeontology. 'Modern' culture arrived in Europe about 50,000 years ago all at once because it was brought there by people who had already gradually developed it over the course of the preceding 150,000 years in Africa. Recent discoveries have shown that people were carving abstract images, creating pigments and making jewellery in southern Africa almost as early as 100,000 years ago.

Controversial evidence that Neanderthals had artistic traditions may mean we have the push the advent of modern-like culture back a lot further than that.