Never limit yourself to popular tourist destinations. Those who love Greece know it well, and it couldn't be otherwise considering the thousands of islands (over 200 populated ones) that make up the Greek territory.
The premise to say that seeing Santorini is not enough to get to know the Cyclades. You must at least also visit Milos (or Milo, Melo) for a more in-depth knowledge of the archipelago.
Visiting the island is not complicated. Maritime connections between Santorini and Milos are guaranteed all the year; alternatively, Milos can also be reached by sea from Piraeus (Athens). Without forgetting, of course, that both islands also have airports, although there are no direct connections to Milos from Italy.
Both islands live thanks to tourism, but Milos doesn't register the same turnout. The circumstance inevitably favored a greater preservation of both natural and urban environments to the benefit of those tourists in search of authenticity and relax.
There are so many things to see: from the beaches which, including the rocky coves, are about 80; to the inhabited centers of Pollonia, Klima, Plaka (the most inhabited) and Adamas (where the port is located).
A curiosity: the very famous Venus de Milo was found in a farm on the island in 1820. The sculpture is located in the Louvre in Paris.