Remove the sirloin tip roast from the packaging and pat it dry. Combine the salt, black pepper, garlic powder, onion powder, and smoked paprika, then season the roast generously on all sides.
Heat a little oil in a skillet over medium-high heat. Sear the roast on all sides until browned. This step is optional, but it adds better color and deeper flavor.
Place the roast in the center of the crockpot. Arrange the baby carrots, sliced onion, and halved or quartered Yukon Gold potatoes around the roast.
Spoon the tomato paste around the vegetables. Pour in enough beef broth to reach slightly above the middle of the roast, then add the bay leaves, balsamic vinegar, Worcestershire sauce, dried thyme, and dried rosemary.
Cover and cook on HIGH for about 6 hours or LOW for about 8 hours. Cooking time can vary depending on the size and thickness of the roast, so continue cooking if needed until the meat is tender.
To test the roast, stick a fork into the meat and gently turn it. The fork should turn with a little resistance and the beef should begin to pull apart easily. If there is still a lot of resistance, continue cooking and check again later.
Once tender, shred the roast and remove the bay leaves. Stir the cooking liquid well so the tomato paste fully combines with the broth, then serve the beef with the vegetables and spoon the savory cooking liquid over the top.