First, make your garlic bread. Slice open your Italian bread and top each half with olive oil, butter, oregano, roasted garlic and salt and pepper. Bake in your smoker at 350 degrees F for 10 minutes until it's nice, bubbly and crispy. Set aside.
Preheat your grill to medium-high heat. Slice your bell peppers, mushrooms and onions. Place in a cast-iron skillet on the grill and cook until translucent, about 10 minutes.
Season your ribeyes. While the vegetables are cooking, reverse sear your ribeyes until medium rare.
Pour your marinara and heat in a saucepan on the grill until warm. Once the marinara is ready, assemble your sandwich: the bottom half of the garlic bread, marinara, steak, vegetables, cheese, vegetables, more cheese. Place back on the grill to warm up and get the cheese nice and bubbly.
Place the top half of the garlic bread on the sandwich, slice the sandwich and serve.