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 3-4 minutes on each side until browned. Remove from heat.
Place sliced onions and minced garlic at the bottom of the slow cooker.
Put the seared roast on top of the onions and garlic in the slow cooker.
In a bowl, whisk together the condensed cream of mushroom soup and beef broth until smooth.
Pour the mushroom soup mixture over the roast in the slow cooker.
Add the carrots, potatoes, and celery around the roast.
Sprinkle dried thyme and dried rosemary evenly over the vegetables and roast.
Cover the slow cooker with its lid and cook on low for 8 hours, or until the meat is tender and easily shredded with a fork.
Once cooked, carefully remove the roast and vegetables from the slow cooker. Let the roast rest for 5 minutes before slicing.
Serve the sliced pot roast with the cooked vegetables and spoon the mushroom sauce from the slow cooker over the top.