Add the oil, butter, onion, carrots, and celery to your Instant Pot. Press the sauté button and cook for 5 minutes, stirring occasionally.
Stir in the garlic, followed by the broth, split peas, ham (if using), smoked paprika, and cumin.
Give it a good stir, then close the lid, make sure the valve is on "sealing", and press the "manual" button to set the timer for it to cook for 15 minutes on high pressure. It'll take about 15 minutes for the Instant Pot to come up to pressure.
Once the countdown has finished, let the pressure release naturally for 15 minutes. You can then do a quick release if you wish, or just let it naturally release for the rest of the time.
Season with salt & pepper if needed.