Instant Pot Shrimp Boil

Name: Instant Pot Shrimp Boil
Ingredients: 1 yellow onion, quartered; 1 head garlic, halved crosswise; 2 ribs celery, cut crosswise into thirds; 3 dried bay leaves; 2 tablespoons old bay seasoning; 2 teaspoons black peppercorns; 2 teaspoons Kosher salt; 1 pound small red potatoes (about 12); 12 ounces andouille sausage, cut into 2 inch pieces; 3 ears corn, husked and cut into thirds; 2 ½ pounds shell on large shrimp (16- to 20-count bag); 1 small lemon, sliced into rounds; 4 tablespoons unsalted butter; Cocktail sauce and lemon wedges, for serving