Turn the Instant Pot to the Saute setting, and add the olive oil and butter. When the butter melts, add the chopped onion, and cook until it caramelizes.
Add the minced garlic, and cook 1 – 2 minutes. Turn off the Instant Pot. Add the tomato sauce, the stewed tomatoes, the tomato paste, and 1 1/2 cups of bottled water.
Allow to cool, and pour into a covered container, or into glass jars. If you’re using jars, you’ll need more than 1 or 2, depending on how large the jars are.