Cook pasta in a large saucepan until al dente according to package instructions, drain, and set aside.
Preheat oven to 400 degrees Fahrenheit. Spray a 9x13 baking dish with cooking spray and set aside.
Heat 2 tablespoons of oil on medium-high heat in a Dutch oven or heavy-bottomed stockpot.
Add chopped onion and bell pepper and cook until onion is translucent and veggies begin to soften, about 3-5 minutes. Add garlic and cook until fragrant, about another minute.
Add ground meat, breaking apart with a wooden spoon, and cook until almost cooked through, about 3-5 minutes. Season meat mixture with salt, pepper, Italian seasoning, garlic powder, paprika, and crushed red pepper. Stir to combine everything.
Add pasta sauce and diced tomatoes and give everything another good stir. Season with more salt and pepper to taste, cover and simmer for 8-10 minutes. Add cooked spaghetti and stir until all ingredients are well combined.
Carefully transfer spaghetti to your prepared baking dish and top with shredded cheeses. Bake spaghetti for 20-25 minutes until cheese is melted and bubbly. Serve spaghetti immediately with cornbread or garlic bread if desired. Enjoy!