Preheat your oven to 425°F (220°C). In a large bowl, toss the sliced peppers, onion, and zucchini with olive oil and spices—smoked paprika, cumin, garlic powder, chili powder, salt, and pepper. Spread them in a single layer on a baking sheet and roast for 20–25 minutes, flipping once halfway through, until lightly charred and tender.