Set the Instant Pot to sauté mode and heat olive oil.
Add beef cubes in batches and sear until browned on all sides. Remove and set aside.
Add onions and garlic to the pot; cook until softened.
Pour in beef broth, Worcestershire sauce, thyme, salt, and pepper. Stir to combine.
Return beef to the pot. Secure the lid, set valve to sealing, and cook on high pressure for 35 minutes.
Allow natural release for 10 minutes, then quick release remaining pressure.
Switch back to sauté mode. Stir in the cornstarch slurry and simmer until gravy thickens.
Serve warm over mashed potatoes, rice, or noodles.