Preheat the oven to 300°F. Pat the chuck roast dry with paper towels.
Mix the flour, salt, black pepper, garlic powder, onion powder, smoked paprika, thyme, and rosemary. Coat the roast on all sides.
Heat olive oil in a Dutch oven over medium-high heat. Sear the roast for 4–5 minutes per side, then remove it from the pot.
Add the onion and celery to the same pot and cook for 4–5 minutes. Add the garlic and tomato paste, then cook for 1–2 minutes.
Pour in a small amount of beef stock and scrape up the browned bits from the bottom of the pot.
Add the remaining beef stock, Lipton Onion Soup Mix, and Worcestershire sauce. Return the roast to the pot and add the fresh herbs and bay leaves.
Cover and bake for 2½ hours.
Add the carrots and potatoes around the roast. Cover and bake for another 1–1½ hours, or until the meat is fork-tender.
Remove the roast and vegetables from the pot. Bring the cooking liquid to a simmer on the stovetop.
Mix the cornstarch and cold water, then stir the slurry into the liquid. Cook for 2–3 minutes, or until the gravy thickens.
Serve the pot roast with the vegetables and spoon the gravy over the top.