Cook the macaroni in well-salted water until 2–3 minutes shy of al dente. Drain well.
Melt the butter in a large stockpot over medium heat. Whisk in the flour and cook for 2–3 minutes.
Gradually whisk in the warm milk, then the heavy cream. Simmer, whisking often, until thickened.
Stir in the Dijon, dry mustard, Worcestershire, garlic powder, onion powder, cayenne (if using), salt, and pepper.
Reduce the heat to low. Whisk in the blended cottage cheese until completely smooth.
Remove from the heat and stir in all of the shredded cheeses except the reserved 700 g, mixing until silky.
Fold in the cooked macaroni and most of the bacon bits, stirring until every piece of pasta is well coated.
Divide between two full-size deep hotel pans (or equivalent casserole dishes).
Sprinkle with the reserved cheese, the remaining bacon bits, and the optional buttered panko topping if using.
Bake at 350°F (175°C) for 25–35 minutes, just until bubbling and lightly browned. Avoid overbaking.