Set the roast on the counter for 30 minutes before preparing. Preheat the oven to 400 F.
Using a large, shallow bowl, combine salt and pepper, dried parsley, dried thyme and the arrowroot starch. Add the roast and rotate to coat throughly on all sides.
Using a large dutch oven, heat over medium heat and add the avocado oil. Once the oil is shimmering, add the roast. Cook for 2-4 minutes on each side or until lightly browned. Set aside on a clean plate.
Reduce the heat to medium low. Pour in the coconut aminos while simultaneously scraping the bottom of the pot with a wooden spoon to remove any browned bits from the bottom of the pan.
Add the sliced onion and toss in the coconut aminos. Allow to cook for 3 minutes, just enough for the onions and garlic to become fragrant. Add the mushrooms and carrots and cook for another 3-4 minutes.
Push the vegetables to the side of the pot, making a space in the center for the roast. Add the roast back to the pot and top with broth, and red wine vinegar. Bundle the herbs with cooking twine and add to the pot.
Transfer to the oven and roast for 30 minutes. Reduce the heat to 300 F and roast for another 3 hours for a 3 lb roast, and about 3 hours and 30 minutes for a 4 lb roast. The internal temperature should be 185-195 F for very tender meat. Remove the lid and discard the herbs.
Allow the roast to rest for a few minutes before transfering to a clean surface. Use a fine mesh strainer or large slotted spoon to spoon out the vegetables, leaving the cooking liquid in the pot. You want the cooking liquid to be smooth, so you can strain it into a bowl if it's easier and return it to the pot.
Combine 3 tbsp of arrowroot starch with about 3 tbsp of water or more beef broth in a measuring cup or bowl.
Set the pot of cooking liquid over medium heat and bring to a low simmer, slowly streaming in the arrowroot starch mixture. Stir constantly to allow it to thicken. If a thicker gravy is desired, mix another tbsp of arrowroot starch with water or broth and add it to the gravy. Once the gravy is your desired consistency, remove it from the heat.
Serve the roast with a side of mashed sweet potato (if desired) and plate with vegetables and shredded roast. Top with gravy and chopped parsley.