Start by trimming excess fat from the pork shoulder and patting it dry with paper towels. Rub the olive oil all over the pork, then season it with salt, black pepper, smoked paprika, garlic powder, onion powder, and cayenne pepper if using.

Place the seasoned pork shoulder in the crockpot. Pour the chicken broth and barbecue sauce over the pork, ensuring it's well coated.

Cover the crockpot and cook on low for 8 hours or on high for 4 hours, until the pork is tender and easily shreds with a fork.

Once cooked, remove the pork from the crockpot and shred it using two forks. Return the shredded pork to the crockpot and stir it into the juices.

To assemble the bowls, divide the cooked rice or quinoa among serving bowls. Top with a generous portion of pulled pork, corn, black beans, diced tomatoes, and avocado slices.

Garnish with chopped cilantro and serve with lime wedges on the side for squeezing over the bowls.