Preheat oven to 350°F. Line a baking sheet with foil or parchment paper.
Start on the meatballs first. In a large bowl, add ground pork, egg, gochujang, gochugaru, Panko breadcrumbs, soy sauce, garlic powder, onion powder, salt, and pepper. Wet your hands and mix until just combined. Use a 1½ tablespoon cookie scooper or heaping tablespoon to form ~15 rounded balls and space them evenly apart on the baking sheet. Set aside for now.
In a large pot, heat avocado oil over medium-high heat. Add onion and mushroom and cook until softened, about 3-4min. Lightly season with salt and pepper and then add garlic and ginger, toasting until fragrant, about 30 seconds. Then add kimchi and kimchi brine, scraping up browned bits on the bottom of the pot.
Add gochujang, gochugaru, fish sauce, coconut sugar, uncooked rice, water, and 1 teaspoon salt to the pot. Turn the heat up and cover with a lid, simmering until rice is al dente, about 20-25 minutes. Stir occasionally to keep the rice from sticking to the bottom of the pot and make sure it's at a high simmer throughout.While the rice is cooking, bake the meatballs for 10-15 minutes or until internal temperature is 135-140°F.
Once the meatballs are done baking, nestle them into the stew. Cook, uncovered, over high heat for 5 minutes or until internal temperature of the meatballs is 145-150°F.
Stir in sesame oil and season to taste. Garnish with green onion and serve while warm.