Drain the canned 3 cans chopped clams juice reserved separately, pouring all the juice into a measuring cups. Set the 3 cans chopped clams juice reserved separately aside. Add bottled 3 cans chopped clams juice reserved separately as needed to bring the total liquid to 2 cups.

In a large pot over medium heat, cook the 4 slices thick-cut bacon pieces until crispy and the fat has rendered, about 6–8 minutes. Use a slotted spoon to transfer the 4 slices thick-cut bacon to a paper towel-lined plate. Leave about 2 tbsp of bacon fat in the pot and discard the rest.

Add the 4 tbsp unsalted butter to the pot with the bacon fat over medium heat. Once melted, add the diced yellow onion and 3 stalks celery. Cook, stirring occasionally, until softened and translucent, about 5–6 minutes. Add the 3 cloves garlic and cook for 1 more minute until fragrant.

Sprinkle the 4 tbsp all-purpose flour over the vegetables and stir constantly for 1–2 minutes to cook out the raw flour taste. The mixture will look thick and paste-like — that's exactly right.

Slowly pour in the reserved 3 cans chopped clams juice reserved separately and 2 cups chicken broth low-sodium, whisking constantly to prevent lumps. Bring to a gentle simmer, stirring frequently, until the broth thickens slightly, about 3–4 minutes.

Add the diced Yukon Gold potatoes peeled and cut into 1/2-inch cubes to the pot. Simmer uncovered over medium-low heat until the 1 ½ lb Yukon Gold potatoes peeled and cut into 1/2-inch cubes are fork-tender, about 15–18 minutes. Stir occasionally and keep the heat low — you want a gentle bubble, not a rolling boil.

Reduce the heat to low. Stir in the 2 cups heavy cream, 1 cup whole milk, 2 tsp Worcestershire sauce, and 1 pinch cayenne pepper (if using). Let the chowder warm through gently for 3–5 minutes. Do not boil after adding the cream or it may curdle.

Add the reserved 3 cans chopped clams juice reserved separately and most of the cooked 4 slices thick-cut bacon back into the pot. Stir gently and heat for 2–3 minutes just until the 3 cans chopped clams juice reserved separately are warmed through. Taste and adjust 1 tsp kosher salt and ½ tsp black pepper as needed.

Ladle into warm bowls. Top with the remaining crispy 4 slices thick-cut bacon, 2 tbsp fresh parsley chopped, and a crack of black pepper. Serve with 6 pieces oyster crackers for serving on the side.