Preheat oven to 425°F. Poke potatoes all over with a fork, rub with olive oil, and season with salt. Wrap in foil. Bake for 60-80 minutes until fully tender.
While potatoes bake, sauté sliced onion and bell pepper in a little olive oil over medium heat for 6-8 minutes until softened. Remove from pan and set aside. In the same skillet, cook thinly sliced sirloin steak on high heat for 3-5 minutes until browned. Season generously with salt, pepper, and garlic powder. Splash in Worcestershire sauce. Reduce heat to low, return veggies to the pan and stir to combine. Layer provolone slices on top and cover pan for 1-2 minutes, just until the cheese melts.
Slice each baked potato open lengthwise and stuff generously with the cheesy Philly steak mixture.
Serve warm, topped with a drizzle of white queso (or low-fat white cheddar) if desired. Finish with crumbled homemade croutons, fresh diced tomatoes, or chopped green scallions.