Set your Instant Pot to the sauté mode. Once hot, add the olive oil.
Add the diced onion to the pot and sauté for about 3 minutes until translucent. Then add the minced garlic and sauté for an additional minute.
Add the carrots, celery, zucchini, and red bell pepper to the pot. Sauté for another 5 minutes until the vegetables begin to soften.
Stir in the quinoa, diced tomatoes (with their juices), vegetable broth, dried Italian herbs, salt, and black pepper.
Close the Instant Pot lid, ensuring the valve is set to 'sealing.' Cook on high pressure for 10 minutes.
Once cooking is complete, allow for a natural release for 5 minutes, then switch the valve to 'venting' to release any remaining pressure.
Open the lid and stir in the torn kale and cannellini beans. Allow the soup to sit for an additional 5-10 minutes for the kale to wilt.
If desired, stir in the lemon juice for added brightness before serving.
Serve hot, garnished with fresh parsley if using.