Fill a 4- to 5-quart saucepan about two-thirds full with water and bring to a rolling boil over high heat.
Add the dry elbow macaroni and stir frequently; cook about 15 minutes until al dente, then drain in a colander and rinse with cold water to stop cooking.
Preheat the oven to 350°F (175°C).
In the same (or a clean) large saucepan over medium-high heat, melt the sliced butter.
Whisk in the flour and cook, whisking constantly, about 2 minutes until the raw flour smell is gone.
Slowly whisk in the whole milk and heavy cream, keeping the mixture smooth and free of lumps.
Add the salt, white pepper, smoked paprika, garlic powder, and onion powder; continue cooking and whisking 4–5 minutes until the sauce thickens and coats the back of a spoon.
Lower heat to low and stir in 1½ cups of the shredded Colby Jack, the shredded gouda, American cheese, and Parmesan until just melted; remove from heat.
Stir the cooked macaroni into the cheese sauce until evenly coated.
Lightly spray a 9×13-inch baking dish with nonstick spray and transfer the macaroni mixture to the dish.
Evenly sprinkle the remaining ½ cup of shredded Colby Jack over the top, then bake uncovered 20–25 minutes until the filling is bubbly and the top is melted (do not brown).
Allow the casserole to rest for a few minutes before serving.