Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Toss the broccoli florets, sliced bell peppers, and zucchini with half of the avocado oil, garlic powder, and half of the sea salt.
Spread the vegetables in a single layer on the baking sheet and roast for 15-18 minutes until tender and slightly caramelized at the edges.
While vegetables roast, pat the snapper fillets completely dry with paper towels and season both sides with the remaining sea salt and black pepper.
Heat the remaining avocado oil in a large cast-iron or stainless steel skillet over medium-high heat until shimmering.
Place the snapper fillets in the pan, skin-side down if applicable, and sear for 3-4 minutes without moving them to develop a golden crust.
Carefully flip the fillets, add the ghee to the pan, and cook for an additional 2-3 minutes while spooning the melted ghee over the fish.
Remove from heat and drizzle the lemon juice over the fish before serving alongside the roasted vegetable medley.