Mashed Potatoes With Crispety Cruncheties

Name: Mashed Potatoes With Crispety Cruncheties
Ingredients: 4 lb. German Butterball or Yukon Gold potatoes, scrubbed; 1 head of garlic, divided; 5 sprigs thyme; 2 tsp. black peppercorns, lightly crushed; 1¼ cups (2½ sticks) unsalted butter; 4 cups (or more) whole milk; 1 Tbsp. (or more) kosher salt; 1 lemon; 2 ½-thick slices country-style bread, torn into 1 pieces; 2 cups kettle-style potato chips (such as Cape Cod); 4 Tbsp. unsalted butter; Kosher salt, freshly ground pepper; 3 sprigs thyme, leaves picked; 1 tsp. hot smoked Spanish paprika; ⅓ cup chopped parsley