In this thread, you can find a good answer by u/KiwiHellenist about the origin of the legend of Atlantis.

I just want to add and emphasise that you won't find any respected historians who claim that Atlantis could have been anything more than a myth made up by Plato to tell a story about Athens. There are so many theories about it, because it is a spectacular story and the idea of an ancient powerful city that was lost is highly appealing.

The only documentaries I have ever seen about Atlantis were ancient aliens-type productions which can be seen as wild speculation at best, and just plain conspiracy theories and dishonest at worst.

If you're fascinated by ancient lost cities, like you say, then I'm afraid you will have to tread very carefully. The overwhelming majority of information you will find online about this topic will be complete pseudo-historical nonsense.

Now, I do understand your fascination. I loved the game Age of Mythology, or the Conan the Barbarian stories, and other pop-culture settings that involve Atlantis. But it's good to regularly remind yourself that these sensational stories are just that. Fictional stories.

The danger is that when you're interesting in such a topic, it's common to gravitate towards the information that feeds your interest. Because it's likely that it's more agreeable to you to see a documentary that implies that Atlantis might have been real, than a real historical answer that boils down to: no, it's just a legend.