Bring a large pot of water to a boil, add a generous pinch of salt, then add 1 lb linguine and cook until al dente. Drain and set aside, reserving 1/2 cup pasta water.
Place the chicken strips in a bowl and season with 1 tsp garlic powder, 1/2 tsp smoked paprika, 1/2 tsp salt, and 1/2 tsp black pepper. Toss until evenly coated.
Heat 2 tbsp olive oil and 2 tbsp butter in a large pan over medium-high heat until the butter foams.
Add the chicken strips in a single layer and sear for 3 minutes without stirring until deeply golden.
Flip the chicken and cook another 2–3 minutes until the edges are crispy. Transfer to a plate and set aside.
Reduce heat to medium, then add the remaining 2 tbsp butter to the same pan and let it melt.
Add 6 minced garlic cloves and sauté for 30–45 seconds until fragrant.
Pour in 2 1/2 cups heavy cream and stir, scraping up the browned bits.
Add 4 oz cubed cream cheese and whisk continuously for 2–3 minutes until smooth.
Lower the heat to low, then add 1 1/2 cups shredded mozzarella one handful at a time, stirring until stretchy.
Add 1 1/2 cups shredded sharp cheddar one handful at a time, stirring until melted.
Add 1 cup grated Parmesan one handful at a time, stirring until smooth.
Stir in 1 tsp Italian seasoning, 1/2 tsp salt, and 1/2 tsp black pepper, then simmer for 2 minutes until thick, glossy, and pooling. Loosen with reserved pasta water if needed.
Add the cooked linguine to the sauce and toss until every strand is heavily coated and buried.
Top the pasta with the seared garlic Parmesan chicken, sprinkle with 2 tbsp chopped parsley, and serve immediately.