Great apes with small brains were not very mobile
Including the human, there are now 13 living taxa of great apes. Except for the human, the great apes are not very mobile. We can be certain that each taxon now lives in the isolated area where it evolved. There were once many other taxa of great ape between Indonesia and Central Africa, but they are now extinct.
(last common ancestor about 6 Ma?)
Bonobo (Pigmy Chimp)
(last common ancestor about 10 Ma?)
Cross River Gorilla
Western Lowland Gorilla
Eastern Lowland Gorilla
(last common ancestor about 15 Ma?)
Genetic studies show that the human is closely related to the chimp, next closely to the gorilla, and next to the orangutan.
The human, after its evolution, had a remarkably large brain. With that brain, it was able to invent shoes and clothing, and tools for defending itself and carrying water and food. Those inventions enabled it to spread out and populate the entire globe. Because of its current spread, we do not know the area where the human evolved its large brain. Since it was small-brained and not yet mobile, the place was presumably near one of the chimp places.
Fossils show that early humans (Homo erectus, Neanderthals, Denisovans, and Homo sapiens) migrated great distances from where they evolved. Genetic studies of living humans show that the area of their origin was somewhere in Africa.