Place the halved potatoes, chopped carrots, and sliced onion in the bottom of the slow cooker to form a base.
Pat the roast dry with paper towels. Rub all sides with garlic powder, onion powder, thyme, paprika, salt, and black pepper.
Set the seasoned roast on top of the vegetables in the slow cooker.
In a small bowl, mix together the beef broth and soy sauce. Pour this mixture evenly over the roast and veggies.
Cover the slow cooker and cook on low for 8 to 10 hours, or high for 4 to 6 hours. Cooking on low is ideal for the most tender results.
Once the roast is fork-tender and shreds easily, remove it along with the vegetables.
To make a quick gravy (optional), whisk 1 tablespoon of cornstarch with 2 tablespoons of cold water. Stir the slurry into the leftover cooking juices and turn the slow cooker to high. Simmer for 5–10 minutes until thickened.
Slice or shred the roast and serve hot with the vegetables and gravy, if using.