Of course all of the “Troys” we’ve found are just cities that got in big wars.
I do trust Plato. Having actually READ Timaeus and Critius I understand that they were his version of Atlas Shrugged and there’s no more an Atlantis than there is a Galts Gulch.
I forget how large Plato’s Atlantis was -but it was huge - a subcontinent, not just some island with a temple. I’m guessing that the “concrete” the guy saw is just conglomerate rock, or perhaps limestone (an old reef).