Place the clams in a pot large enough to hold them comfortably and cover with water. Let sit for 30 minutes. Drain the clams and rinse with cold running water several times. (You can do this up to 7 million times and you will never remove all the sand. Let this be a lesson in life to you.)
Place the cleaned clams in a large Dutch oven or heavy-bottomed pot and add enough wine to go about halfway up the clams, about the whole bottle. Tie the thyme, oregano and bay leaves in a bundle and add to the pot. Cover with a tight-fitting lid and steam until the clams open completely, 15 to 20 minutes, or about 8 minutes after the liquid boils. Once the clams are all opened, remove them with a slotted spoon to a sheet pan to cool for a few minutes. Strain the clam broth through a fine strainer, reserving the liquid.
Put a large Dutch oven over medium heat and add the olive oil. Once heated, add the guanciale and prosciutto and begin to render, 2 to 3 minutes. Remove some pieces of crispy prosciutto for garnish, if possible. If not, move on. Add the onion, garlic and celery to the pot and gently sweat over medium-low heat until they begin to soften up, about 3 minutes. Add the diced potatoes and cook to allow more fat to render from the prosciutto and guanciale and for the vegetables to fully soften, another 10 to 15 minutes.
Meanwhile, remove the clams from the shells and chop roughly; don't turn them into dust—big pieces are good. Add the clams and the Calabrian chile paste to the potato pot and add about two-thirds of the reserved clam broth. Let the chowder begin to gently heat up and come to a simmer. Once at a simmer, add the heavy cream, more or less depending on your desired taste; for brothy, add a smaller amount of the cream. Always taste the batch; it may need a touch of sea salt, it may not—some clams are saltier than others.
To serve, place a well-proportioned ladle of chowder in a bowl and garnish with some celery leaves, reserved crispy prosciutto (if any) and cracked black pepper.