Place corned beef, onion, garlic, butter, spices, and 4 cups of water into the instant pot.
Cook on 90 minutes using the meat/stew setting or high pressure for 90 minutes. Once time is up, quick release pressure. Remove corned beef to a platter and cover with foil. Let rest while cooking the vegetables.
Without discarding liquid, add sauerkraut and cream to the pressure cooker, you may remove the rack if desired.
Cook at high pressure for 4-5 minutes. Do a quick pressure release before removing vegetables.