I would go along with a tradition / mythology of Sundaland as "Mu", but not Atlantis..
Atlantis, if indeed it did exist literally, was almost definitely Santorini..
But as a culture, I believe the Atlanteans were more likely Santorini, Crete, Cyprus, Malta, etc... A seafaring, Island dwelling society built on trade..
The Pillars of Hercules referred to are the ancient ones in the Mediterranean, not the gateway to the Atlantic..
The people mentioned by the Egyptians were the "sea people", which were eventually dispersed throughout the Mediterranean and along the coast of Spain.. ( later referred to as Philistines, possibly Phoenicians, later, Canaanites )
Mu, on the other hand, was more ancient, and far larger.. I would be more inclined to believe that Sundaland / Mu are the same..
There may have been some confusion of legends, blending aspects of the two civilizations, or possibly legend through descent.. ( Atlantean civilization descended from survivors of Sundaland / Mu culture(s) ...
This might account for the erroneous timeline in which Plato claims Atlantis was 10,000 years old... ( in his time)
This may have been a reference to where the Atlanteans came from.. An ancient, 10,000 year old civilization that once thrived in Ice Age Indonesia/Sundaland...
Having migrated to the Mediterranean some 7,000 years ago, their advanced culture would have been able to establish itself with virtually no resistance on the islands, and eventually rule the Mediterranean basin for a couple thousand years before any seriously civilized culture could advance enough to threaten them..
If they had remained peaceful traders they might have been able to survive, but "good living" turned them to practice of slavery.. ( or local influences, who knows ?? )
They would have eventually been overwhelmed by sheer numbers anyway, but natural disaster quickened their demise...
Anyways, that's my 2 cents worth..