Heat oven to 350°F. Line a rimmed sheet pan with foil and set a rack on top.
Cook bacon in a skillet over medium heat until crisp, 6–8 minutes. Drain and cool.
Stir breadcrumbs and milk in a large bowl. Let stand 5 minutes to hydrate.
Add beef, mayonnaise, onion, pickles, 2 tbsp ketchup, 1 tbsp mustard, Worcestershire, garlic powder, salt, and pepper.
Mix gently with half the bacon and half the cheddar just until combined. Do not overwork.
Shape mixture into a 9-inch loaf on the rack. Smooth the top and sides.
Whisk glaze ketchup, mustard, and brown sugar. Brush over the loaf.
Bake 50–60 minutes, until internal temp reaches 160°F. Sprinkle remaining cheddar and bacon on top for the last 5 minutes.
Rest 10 minutes before slicing. Serve with extra pickles if you like.