Vanished civilization

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I need some advice regarding my campaign's history.

In the setting's bronze age (so, 3000ish years before the game takes place) there was a civilization that that gained a mastery of magic surpassing all the others. Using their mastery, they created what they intended to be permanent teleportation circles between their major settlements. They began colonizing other lands, taking ships across the oceans to other continents, and established teleportation circles in those places, too. They kept the method for making these circles secret, ensuring they had a monopoly on them.

Unfortunately, all teleportation no matter how minor briefly touches the Void, a transitory but terrifying chaos plane where the rules of reality break down the deeper you go, and which is inhabited by horrifying entities that defy the laws of nature by their mere existence.

The repeated use of these circles over the centuries caused them all to go haywire at once and plunge the cities they were located in into the Void, never to be found again. This left behind vast canyons where their cities were located, and also very little evidence that they even existed, thanks to the nascent state of written language (think proto-writing, pic related) in the civilizations that existed at the same time and the fact that their major population centers up and vanished.

My question is, given the state of language, what information about this civilization would logically have survived over the millennia? Would there be legends about this lost civilization?