Preheat the oven to 425°F (220°C) and line a large baking sheet with parchment paper or lightly grease it.
Place the potatoes on the sheet pan, drizzle with 1 tablespoon olive oil, season lightly with salt and pepper, and roast for 10 minutes.
In a large bowl, combine the steak, broccoli, bell peppers, zucchini, and onion.
Add the remaining olive oil, garlic, Italian seasoning, smoked paprika, onion powder, salt, and black pepper. Toss until everything is evenly coated.
Remove the partially cooked potatoes from the oven and add the steak and vegetables to the baking sheet in a single layer.
Roast for 12–15 minutes, stirring halfway through, until the vegetables are tender and the steak reaches your preferred doneness.
Remove from the oven and let the steak rest for about 5 minutes.
Sprinkle with fresh parsley and serve with lemon wedges if desired.