Pat the beef dry with paper towels. Season generously with salt and pepper on all sides.
Heat the olive oil in a skillet over high heat. Sear the beef until it forms a deep, dark crust, approximately 7 minutes.
Transfer the seared beef to the slow cooker.
Using the same skillet, sauté the onion and garlic for about 2 minutes until the onion is nicely browned.
Add the wine to the skillet, allowing it to reduce by half, then pour this mixture into the slow cooker.
Combine the flour with about 1 cup of the beef broth, mixing until there are only small lumps. Add this to the slow cooker.
Pour in the remaining beef broth, then add the carrots, celery, rosemary, and thyme.
Cover and cook on LOW for 5 hours. (Alternatively, pressure cook on HIGH for 45 minutes).
Add the potatoes to the slow cooker and continue to cook on LOW for an additional 3 hours. (Or pressure cook on HIGH for 10 minutes; see Note 3b).
Once done, remove the beef from the slow cooker and let it rest for 5 minutes before slicing it thickly.
Taste the sauce and adjust the salt and pepper as needed.
Serve the beef with the vegetables and a generous amount of the sauce. Bread, such as No Knead Dinner Rolls, No Yeast Irish Soda Bread, or Cheese Muffins, makes an excellent accompaniment for mopping up the delicious sauce.