While I do not doubt that Northern Africa has cradled human civilization for a long time, to me, connecting the Richat structure and Plato is stretching it quite a bit, though. Why not say Plato's Atlantis is actually Göbekli Tepe – it's in the wrong direction and also not an island, but there are concentric structures and is actual man made?

If we are to neglect that Plato clearly states that his rhetorical vehicle is situated outside of Africa, but the Richat structure is in the then known parts of Africa, why should direction matter? While we may discuss the Richat structure, we should do so separately. There's no need to connect these things and no indication of why we should do so.

Regarding features, given the total population of that time (at least, as far as our estimates go), controlling a circular structure of 25km diameter may have been a bit ambitious. (It may have been pretty disadvantageous in actuality, as you would have to control and defend rather extensive perimeters with what would only account to thousands (in the low single digits). And, if you failed to do so, the very same features would have hosted your enemies. — Compare this to what Plato thought to be a more realistic size for what must have been then a remarkably extensive population.)