Set 6-qt Instant Pot® to the high saute setting. Add bacon and cook until brown and crispy, about 6-8 minutes. Transfer to a paper towel-lined plate.
Add garlic and onion. Cook, stirring frequently until onions have become translucent, about 2-3 minutes.
Stir in bacon, potatoes, corn, vegetable stock, thyme, and cayenne pepper; season with salt and pepper, to taste. Select manual setting; adjust the pressure to high, and set the timer for 10 minutes. When finished cooking, quick-release pressure according to manufacturer’s directions.
In a small bowl, whisk together heavy cream and arrowroot powder; set aside.
Select high sauté setting. Bring to a boil; stir in heavy cream mixture and cook, stirring frequently, until slightly thickened, about 4-5 minutes. If the mixture is too thick, add more vegetable stock as needed until desired consistency is reached.
Serve immediately, garnished with chives, if desired.