Preheat oven to 400°F (200°C) and line a baking sheet with parchment paper.
Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Add sliced steak and sear until browned. Remove steak from skillet and set aside.
Add remaining olive oil to the same skillet. Sauté onions and bell peppers until softened and slightly caramelized, approximately 5 to 7 minutes.
Return the steak to the skillet, season with salt, black pepper, and garlic powder, and mix thoroughly. Remove from heat and let cool slightly.
On a lightly floured surface, roll the pizza dough into a large rectangle approximately 10x14 inches.
Spread the steak and vegetable mixture evenly over the dough, leaving a 1-inch border on all sides. Sprinkle the mozzarella cheese over the filling.
Starting from the long side, tightly roll the dough into a log. Pinch the ends and the seam to seal completely.
Place the stromboli seam-side down on the prepared baking sheet. Brush the top with the egg wash and sprinkle with dried oregano.
Use a sharp knife to cut 3 or 4 small diagonal slits on the top of the dough for steam to escape.
Bake for 20-25 minutes or until the crust is golden brown and the cheese is melted.
Allow to rest for 5 minutes before slicing and serving.