The modern world had little or no knowledge of Atlantis before Ignatius Donnelly's book in the 19th century, and has for the most part, swallowed his lead since, ie attempting to force a literal translation of Plato's work. However, Plato was primarily a philosopher, not an historian. It has been argued by many that Plato's Atlantis is a myth, allegorically relating grand events in Man's early history, perhaps in the days when the gods ("Atlanteans"?) controlled Man on earth. As with most myths, ideas were cloaked in an adventure story that common folks could embrace. Another Garden of Eden-type tale perhaps - the gods' creation of Man and how Man dealt with it?
If indeed there was a "super civilization" in the Mediterranean region in forgotten ancient days - which I certainly accept (perhaps in the Ice Age era and earlier) - it makes perfect sense to me that it would have been based in the Eastern Mediterranean, where evidence of sophisticated ancient human development is most prevalent. Southern Spain is interesting, yes - and there was a very strong early Phoenician presence there that might be mistaken for "Atlantis" - but Turkey is of greater interest, IMO. Especially concerning the rumors in the Western Turkish region centering on today's Manisa, and further west, where there are many more very old sites, the most intriguing being perhaps such places as Göbekli Tepe and Mount Ararat. From there we move into land-locked Sumer, next door to Turkey. Perhaps Plato's Atlantis allegories were dealing with the Sumerians' god pantheon, which eventually was adopted by the Greeks and Romans.