Cook rice in a large pot of generously salted boiling water, as you would cook pasta, until it is tender, about 30 minutes.
Meanwhile, season each side of the steak with 1/4 teaspoon of the salt and freshly ground black pepper, to taste. Preheat a large nonstick skillet over medium-high heat and spray the steak with nonstick spray. Add the steak and cook until browned, about 5 minutes. Flip and continue cooking on the other side until browned, 5 minutes more. Transfer the cooked steak to a plate and let rest.
Heat the oil in the same skillet over medium-high heat. Add the garlic, onion, and bell pepper. Cook, covered, over medium heat, stirring occasionally, until the vegetables are soft, about 10 minutes. Stir in the tomatoes, broken spaghetti, chicken broth, and saffron and cook until the pasta is cooked through, 8 minutes. Drain the rice and add to the pot along with the peas. Stir until warm. Arrange the shrimp on top of the rice, cover and let shrimp steam until shrimp is just cooked through and pink, about 3 minutes.
While the shrimp cooks, slice steak against the grain into 1/4-inch thick slices. Lay over the paella. Remove from the heat. Scatter cilantro and olives over the top and serve warm from the pan.