Heat a generous drizzle of olive oil in a large pot over medium heat. Add diced onion, sliced carrots, sliced celery, and diced zucchini. Sauté for 2-3 minutes until fragrant and the onion turns translucent.

Stir in salt and Italian seasoning, ensuring that each vegetable is coated evenly. Sauté for an additional minute.

Add diced fresh tomatoes and tomato sauce to the pot. Pour in chopped green beans, rinsed white kidney beans, and dry shell pasta, followed by water or vegetable broth. Stir together and bring to a gentle simmer.

Allow the soup to simmer for about 15-20 minutes on low heat, stirring occasionally. For Instant Pot version, seal the lid and cook on high pressure for 5 minutes.

If cooking on the stovetop, ensure pasta is tender and vegetables are soft but not mushy. For Instant Pot, perform a quick release of the pressure, then stir the soup.

Ladle the warm soup into bowls and garnish with fresh chopped parsley. Serve immediately, perhaps with crusty bread for dipping.