The stories you remember were published by the Spanish comic magazine "Trinca" in biweekly installments between 1970 and 1973. Their artist was Alfonso Azpiri and the scriptwriter of most of them was Carlos Saiz Cidoncha.
This is the cover of the number 61 (year 1973) that includes the story "Superviviente," which is the one about the Atlantis survivor.
This is Jack McDevitt's The Devil's Eye
It's one of his Alex Benedict books, so it is indeed part of a series.
From the link:
Alex Benedict, interstellar antiquities dealer, and his assistant, Chase Kolpath, are on vacation when they receive a cryptic message from Celebrated writer Vicki Greene, whom neither has ever met, asking for help. But when they ...