Instant Pot Pulled Porchetta Sandwiches

Name: Instant Pot Pulled Porchetta Sandwiches
Ingredients: 1 tablespoon plus 1 1/2 teaspoons fennel seeds; 1 teaspoon whole black peppercorns; 1 tablespoon plus 1/2 teaspoons garlic powder; 1 tablespoon plus 3/4 teaspoon kosher salt, divided, plus more as needed; 10 sprigs fresh rosemary; 5 sprigs fresh sage; 1/2 medium bunch fresh parsley; 1 medium lemon; 3 pounds boneless pork shoulder roast; 1 large white or yellow onion; 2 tablespoons olive oil; 1 cup low-sodium chicken broth; 1/2 cup dry white wine; 1/4 cup red wine vinegar; 1 1/2 teaspoons granulated sugar; 6 medium Fresno peppers or red jalapeños peppers; 8 ciabatta rolls; 2 cups baby arugula (about 2 ounces)