Place a pizza stone or inverted rimmed baking sheet on the bottom rack of the oven and preheat to 450 degrees F.
Dust a piece of parchment lightly with flour. Stretch or roll out the pizza dough into a 14-inch round on the parchment, then transfer the dough on the parchment to a pizza peel or another inverted rimmed baking sheet.
Spread the Alfredo sauce on the pizza dough and sprinkle with the mozzarella. Combine the garlic powder and Italian seasoning in a small bowl, then sprinkle over the cheese. Top with the pickles.
Slide the pizza on the parchment onto the heated stone or baking sheet and bake until the crust is golden, 12 to 14 minutes. Garnish with dill sprigs and serve with ranch dressing for dipping.