Set the Instant Pot to "Sauté" mode and add olive oil. Sauté the onion and garlic for 2-3 minutes until fragrant. Add the red bell pepper and carrots, and sauté for another 2 minutes.
Cancel the "Sauté" mode. Add the cabbage, potatoes, sweet potatoes, and broccoli. Stir well to combine.
Add the tomato sauce over the vegetables and the parsley.
Close the lid and set the valve to the "Sealing" position. Select "Pressure Cook" or "Manual" mode and set the timer for 12 minutes on high pressure.
Once the cooking time is complete, allow the pressure to release naturally for 3 to 4 more minutes, then carefully do a quick release by moving the valve to "Venting."
Open the lid, stir the stew, and adjust the seasoning if necessary.Serve hot, garnished with fresh parsley, alongside crusty bread or rice.