Season the beef chuck roast evenly with salt and black pepper on all sides.
Heat olive oil in a large skillet over medium-high heat. Sear the roast for 4-5 minutes on each side until browned. Transfer the roast to the slow cooker.
In the same skillet, add the sliced onion and minced garlic. Sauté for 2-3 minutes until softened, then add the sliced mushrooms and cook for an additional 5 minutes until they release their moisture and begin to brown.
Add the sautéed onion, garlic, and mushrooms to the slow cooker, placing them around and on top of the roast.
Add the carrots and celery pieces to the slow cooker around the roast.
In a medium bowl, whisk together beef broth, red wine, tomato paste, and Worcestershire sauce. Pour this mixture over the roast and vegetables in the slow cooker.
Add the fresh rosemary, thyme sprigs, and bay leaves to the slow cooker.
Cover and cook on low for 8 hours, or until the beef is tender and easily shredded with a fork.
Remove the rosemary, thyme sprigs, and bay leaves before serving. Slice or shred the roast and serve with the cooked vegetables and mushrooms, spooning the cooking liquid over the top.