This is a non-answer, How would you detect it then?
I don't know about Atlantis specifically but where would we expect to find previous ancient civilizations?
All of human history we congregate around rivers, this is where civilizations arise, due to available fresh water. As we advance technologically we start to build in bays, basins, deltas, still on rivers, but near the ocean, for trade.
All the places on earth where any of these ancient civilizations would have existed are all now under 100-400 feet of water. Yet when we look along the coasts underwater we actually do find the remains of what could have been ancient egyptian levels of ruins, the bimini roads, yonaguni, the malta rail lines, etc.
The black sea and parts of the med, the indonesian archipelago before it was islands, Caribbean before it was underwater, even the north sea before it was underwater is where you would, (and ironically, it is where we do, almost universally, any time we bother to look) find evidence.
Shit like Gobekli and Gunung, even Malta were basically built by backward ass hilltribes men living in the mountains like deliverance hillbillies when the last time civilization was wiped out and the few survivors came by and taught them how to have a civilization. It's a shame that all we have to show for it is what they managed to build during that time before the advanced knowledge and engineering was lost and all that remained and was passed down was myths and legends and the basics like agriculture and basic hygiene.