Preheat oven to 220°C (425°F). Line one or two large baking sheets with parchment paper.
Arrange the flatbreads in a single layer on the prepared baking sheets. Brush the surface of each flatbread lightly with olive oil.
Spread 2 tablespoons (30 ml) of tomato pizza sauce evenly over each flatbread, leaving a 1 cm border around the edge.
Sprinkle garlic powder and dried oregano evenly over the sauce on each flatbread.
Distribute the shredded mozzarella cheese evenly across all four flatbreads, approximately 50 g per piece.
Arrange the pepperoni, sliced bell pepper, red onion, and black olives evenly over the cheese layer. Season lightly with salt and black pepper.
Transfer the baking sheets to the preheated oven and bake for 8–10 minutes, until the cheese is fully melted and bubbling and the flatbread edges are golden and crisp.
Remove from oven and allow to rest for 1–2 minutes. Top each flatbread with fresh basil leaves and a pinch of crushed red pepper flakes if desired.
Slice each flatbread into thirds or quarters using a sharp pizza cutter or chef's knife. Serve immediately.