Lightly grease the Instant Pot insert and set the cooker to Sauté.
Add the ground beef and cook until browned on the bottom, then flip and break it apart; continue until no pink remains.
Drain any excess grease from the pot, then turn the Instant Pot off.
Stir in the garlic powder, salt, Italian seasoning, black pepper, crushed red pepper flakes, and tomato paste until evenly combined with the beef.
Break the spaghetti in half and spread it over the beef in an even layer.
Pour the water and the jar of spaghetti sauce over the spaghetti, pressing the pasta down so it is submerged.
Close the lid, set the valve to sealing, and pressure cook on High for 6 minutes.
Perform a quick pressure release, open the lid, then add the cream cheese pieces and Parmesan.
Stir until the cheeses are combined and creamy, then replace the lid and let sit a few minutes to fully melt; stir again before serving.
