Place bacon strips in a cold skillet and cook over medium heat until crisp. Transfer to a paper towel–lined plate to drain and crumble when cool.

In the same skillet, leave 1 tablespoon bacon fat, add ground beef, season with garlic powder, onion powder, salt, and pepper, and cook until browned and cooked through. Drain excess fat.

Spray the slow cooker insert with nonstick spray or rub lightly with reserved bacon fat to prevent sticking.

In a bowl, blend softened cream cheese, mayonnaise, ketchup, and mustard until smooth and lump-free.

Add browned beef to the slow cooker, spread evenly, then top with the cream cheese mixture, diced onion, and pickle relish.

Sprinkle crumbled bacon and shredded cheddar cheese over the layered ingredients.

Cover and cook on LOW for 2 hours or HIGH for 1 hour without lifting the lid.

Stir the dip until creamy and well combined, then top with green onions, diced tomatoes, or jalapeños, if desired.