Preheat oven to 375°F (190°C).
In a large bowl, combine ground beef, breadcrumbs, onion, garlic, milk, eggs, Worcestershire sauce, salt, pepper, and thyme. Mix until just combined.
Shape the mixture into a loaf and place it in a baking dish.
In a small bowl, mix ketchup, brown sugar, and apple cider vinegar to create the glaze.
Spread half of the glaze over the meatloaf before baking.
Bake for 1 hour, then spread the remaining glaze over the top and bake for an additional 15 minutes, or until the meatloaf reaches an internal temperature of 160°F (71°C).