Pat the chuck roast dry with paper towels, and season it generously with salt and pepper on all sides. Set aside.

In a large sauté pan, heat olive oil over medium-high heat. Add the seasoned roast and sear for 4 to 5 minutes on each side until browned. Transfer to the slow cooker.

Reduce heat to medium, add sliced onion with a pinch of salt and pepper, and sauté for about 4 minutes until tender.

Add minced garlic, tomato paste, brown sugar, Italian seasoning, garlic powder, onion powder, and chili powder to onions; cook for an additional minute.

Deglaze the pan with a few splashes of beef stock, scraping brown bits. Transfer the mixture to the slow cooker over the roast.

Arrange carrots and potatoes around the roast; pour in the remaining beef stock to submerge the vegetables.

Nestle thyme and rosemary sprigs with bay leaves into the slow cooker. Adjust salt and pepper to taste.

Cover the slow cooker and cook on low for 8 to 10 hours or high for 4 to 6 hours until fork-tender.

Remove the roast and strain the cooking liquid into a saucepan; discard solids.

Mix cornstarch with cold water to form a slurry and stir into the strained cooking liquid; simmer until gravy thickens.

Shred or slice the pot roast, serve alongside carrots and potatoes, and drizzle with gravy. Garnish with parsley.