Season 2 lbs. stew meat with some salt and pepper. Place seasoned beef in a large bowl and sprinkle with 1/3 c. flour. Toss until evenly coated.
Place 1 tablespoon oil in the bottom of the pressure cooker and turn to “Sauté” setting (high). When hot, add half the meat and brown for ~2 minutes (until it easily releases), flip, and cook another 2 minutes. Remove, add 1 tablespoon oil, and repeat with remaining beef.
Add 1 tablespoon oil and cut onion to pot and cook 2-3 minutes. Add 4 cloves minced garlic and cook another 30 seconds. Add 1/2 cup wine and deglaze pan (Scrape the browned bits off the bottom of the pot with a wooden spoon until wine is reduced by half. ~3 minutes). Turn off Instant pot.
Add in the 2 c. beef broth, 8 oz. tomato sauce, 2 T. Worcestershire sauce, 2 bay leaves, 2 sprigs thyme, 1 tsp. Italian seasoning, 1 tsp. salt, and 1/2 tsp. pepper. Stir together. Add the browned beef, 1.5 lbs. potatoes, 5 cut carrots, and 3 cut ribs celery and stir.
Place the lid on the pot, close the release valve, and select "pressure cook" and cook on high pressure for 20 minutes followed by a 10 minute natural release. Turn valve to release remaining pressure. Remove lid once the float drops.
Set pressure cooker to "sauté". Mix cornstarch with cold water and add to the pot. Gently stir in and allow to cook and thicken for 2-3 minutes. Remove bay leaves and thyme sprigs and serve.