Instant Pot Potato Leek Soup

Name: Instant Pot Potato Leek Soup
Ingredients: 3 tbsp. salted butter; 3 large leeks, white and green parts only, thinly sliced and rinsed; 2 stalked celery, chopped; 2 tsp. kosher salt; 1/2 tsp. black pepper, plus more to taste; 3 garlic cloves, chopped; 6 c. vegetable broth; 6 sprigs fresh thyme, plus leaves for topping; 4 medium russet potatoes (about 2 1/2 pounds), peeled and quartered; 1 bay leaf; 1 c. heavy cream, plus more for topping; 1 c. frozen peas, thawed; 4 oz. goat cheese, at room temperature; 1 tsp. grated lemon zest, plus 1 tablespoon lemon juice; 1 tbsp. chopped fresh chives; 1/4 tsp. kosher salt; 1/4 tsp. black pepper; 12 baguette slices, toasted