Spray the inside of a slow cooker with cooking spray.
Place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned, about 10 minutes. Drain bacon slices on paper towels and crumble.
Spray a skillet with cooking spray and place over medium heat; cook and stir onion, red bell pepper, and garlic until onion is softened, about 5 minutes. Stir potatoes into onion mixture. Spoon 1/3 the potato mixture into the slow cooker; add 1/3 the bacon and 1/3 the Cheddar cheese. Repeat layering with remaining ingredients, ending with cheese.
Whisk eggs, milk, dill, salt, and pepper together in a bowl; pour over ingredients in slow cooker.