Sear the Beef: Set the Instant Pot to "Sauté" mode and add olive oil. Season the roast with salt and pepper. Sear for about 4 minutes on each side until browned. Remove the roast and set it aside.
Sauté the Vegetables: Add chopped onion and garlic to the Instant Pot and sauté for 3 minutes, stirring occasionally.
Deglaze the Pot: Pour in the beef broth and Worcestershire sauce, scraping up any browned bits from the bottom. Add thyme and rosemary.
Pressure Cook the Roast: Return the seared roast to the pot, lock the lid, and cook on high pressure for 60 minutes. Let the pressure naturally release for 10 minutes before carefully venting the remaining pressure.
Remove the Roast: Take the roast out of the Instant Pot and tent it with foil to rest.
Cook Vegetables: Add the carrots and potatoes to the Instant Pot and cook on high pressure for an additional 5-8 minutes, depending on desired tenderness. Quick release the pressure when done.
Make the Gravy: Set the Instant Pot to "Sauté" mode and stir in the cornstarch slurry into the cooking liquid to thicken the sauce into gravy. Stir until the gravy reaches your desired consistency.
Serve: Slice the rested roast and serve it with the cooked vegetables and gravy.