Instant Pot Vegetable Soup

Name: Instant Pot Vegetable Soup
Ingredients: 2 medium carrots (6 to 8 ounces total); 1 medium zucchini (about 8 ounces); 1 pound large Yukon Gold or red potatoes (3 to 4); 1 medium yellow onion; 2 large stalks celery (4 to 5 ounces total); 2 cloves garlic; 3/4 teaspoon dried thyme, or 2 fresh thyme sprigs; 2 tablespoons olive oil; 2 teaspoons kosher salt, divided; 1 (32-ounce) carton low-sodium chicken or vegetable broth; 1 (14.5-ounce) can diced tomatoes; 2 packed cups baby spinach (about 2 ounces); Freshly ground black pepper; Chopped fresh parsley leaves or basil pesto , for serving (optional)