Press saute mode on a 6-quart Instant Pot. Add oil for one minute until hot. Saute onion until soft, about two minutes, then add garlic, celery, carrot, and Italian seasoning and cook for one minute.
Add the red lentils, uncooked pasta, water, vegetable broth, salt, and cayenne pepper.
Press Cancel/Off, then close the lid. Press Manual/Pressure Cook and set for 6 minutes.
When finished cooking, quick-release pressure safely. Open the lid and stir, season with salt if needed, garnish with parsley. Serve immediately.