Cook the pasta: Bring a large pot of salted water to a boil and cook the linguine according to package instructions. Drain, reserving about 1 cup of pasta water, and set aside.

Prepare the chicken: Heat olive oil in a large skillet over medium heat. Add chicken, sprinkle with Cajun seasoning, smoked paprika, garlic powder, onion powder, salt, and pepper. Cook for 5-7 minutes until chicken is cooked through and golden brown. Remove chicken from skillet and set aside.

Make the sauce: In the same skillet, melt butter over medium heat. Add garlic and sauté for 1-2 minutes until fragrant. Stir in flour to form a roux and cook for 1 minute, whisking constantly.

Add the liquids: Gradually whisk in whole milk and chicken broth. Bring to a simmer and cook for about 5 minutes until thickened.

Incorporate the cheese: Add softened cream cheese and whisk until melted and smooth. Stir in 1 1/2 cups shredded mozzarella and Parmesan cheese until fully melted and the sauce is creamy. Adjust seasoning with salt and pepper to taste. Add reserved pasta water to reach desired sauce consistency.

Combine the chicken and pasta: Add chicken back into the skillet and stir to combine with the sauce. Add cooked linguine and toss everything together, ensuring the pasta is well coated in the sauce. Add more pasta water if needed to loosen the sauce.

Serve: Plate the pasta and garnish with remaining shredded mozzarella and red pepper flakes if desired. Serve immediately.