Choose the Sauté mode and let the pot heat up for a couple of minutes before adding the olive oil. Once the oil is hot, add celery, carrots, onions, and a pinch of salt. Cook until the vegetables softened, about 5-7 minutes. Add a bit more oil, if needed.
Add the red pepper flakes and garlic, and cook for 1 minute, stirring often, to prevent burning.
Add the vegetable broth to deglaze the instant pot, using a wooden spoon to scrape up any browned bits on the bottom of the pot. Add black pepper to taste, 1 teaspoon salt, potatoes, green beans, cabbage, chickpeas, thyme, rosemary, tomatoes, and bay leaf. Stir well.
Place the lid on, turn the valve to sealing, and select the Pressure Cook setting at high pressure for 5 minutes. If you would like your veggies less tender cook the soup on low pressure. Cook longer if you'd like your vegetables even more tender. Note >It will take approximately 15 minutes to come to pressure and begin counting down. Skip the next step if you're not making the gremolata.
Make the Gremolata (optional). Finely chop the basil and parsley. Next, zest the lemons on top of this mixture, be sure to not zest the white pith underneath the skin. Mix the lemon zest and garlic into the herbs and chop again until the herbs are finely minced. Sprinkle with some coarse or flaky sea salt.
Once the cooking time is complete, allow the pressure to naturally release for 8 - 10 minutes. Then switch the pressure release knob from Sealing to Venting to release any remaining steam.
Stir in the kale. Select the Sauté mode and heat until the kale is wilted, about 2-3 minutes. Taste & adjust seasonings, adding more salt if needed. Note: feel free to add a teaspoon of maple syrup to balance the acidity of the tomatoes. When the soup is done, remove the bay leaf.
Serve the soup in bowls and sprinkle a generous amount of the Gremolata over each bowl, a drizzle of the extra virgin olive oil, and serve with bread.