Turn the Instant Pot to Sauté mode and heat 2 tablespoons Olive oil. Add diced 1 medium Onion and cook until soft and translucent, about 3–4 minutes.
Stir in minced 3 cloves Garlic and cook for 30 seconds until fragrant.
Add 1 1/2 pounds Ground beef and cook until browned, breaking it up with a spoon. Drain excess fat if needed.
Stir in 28 ounces Tomato sauce, 6 ounces Tomato paste and 14 ounces Diced tomatoes, mixing well.
Add 2 teaspoons Italian seasoning,1 1/2 teaspoons Salt, 1/2 teaspoon Black pepper, and optional 1/4 teaspoon Red pepper flakes and 1 teaspoon Sugar. Stir until combined.
Close the lid, set the valve to Sealing, and cook on Manual/Pressure Cook mode for 10 minutes.
Once done, allow natural pressure release for 5 minutes, then carefully do a quick release for any remaining pressure.
Stir the sauce, adjust seasoning if needed, and garnish with fresh 2 tablespoons Fresh basil or parsley. Serve over spaghetti, lasagna noodles, or your favorite pasta.