Guillaume Delaage is the author of a number of books on ancient mysteries and esotericism. He frequently refers to Helena Blavatsky and holds her writing in high regard. On his website there is a six-part article(a) on Atlantis. He reviews the leading theories, but in the final part seems to find the theories of Otto Muck the most convincing.
(a)https://www.guillaume-delaage.com/articles/01-civilisations/civilisations-disparues/civ_atlantide1.html (French) (This is a six-part paper, to see the other five parts just change the number after ‘atlantide’.)