Preheat the oven to 325°F (163°C).
Pat the beef chuck roast dry with paper towels. Season all sides evenly with kosher salt and black pepper.
Heat the vegetable oil in a large Dutch oven or oven-safe heavy pot over medium-high heat until shimmering.
Add the beef roast to the pot and sear on all sides until deeply browned, about 4 minutes per side. Remove the roast and set aside.
Add the onion wedges, minced garlic, carrots, and celery to the pot. Cook, stirring occasionally, until the vegetables begin to soften and brown slightly, about 5 minutes.
Stir in the tomato paste and cook for 1 minute to deepen the flavor.
Pour in the beef broth and red wine, scraping the bottom of the pot with a wooden spoon to loosen any browned bits.
Return the beef roast to the pot. Add the rosemary, thyme, and bay leaves.
Bring the liquid to a simmer on the stovetop, then cover the pot with a lid and transfer it to the preheated oven.
Cook the pot roast in the oven for 3 to 3 ½ hours, or until the meat is fork-tender and easily pulls apart.
Remove the pot from the oven. Transfer the roast to a cutting board and tent with foil to keep warm.
Strain the cooking liquid into a saucepan, discarding the herbs and vegetables.
Place the saucepan over medium heat. In a small bowl, whisk together the all-purpose flour with 2 tablespoons of cold water to create a slurry.
Gradually whisk the slurry into the simmering liquid and cook until the sauce thickens, about 3 minutes.
Slice or shred the beef roast and serve with the thickened sauce poured over the top.