Combine Greek yogurt, mustard, ketchup, relish, garlic powder, onion powder, and smoked paprika in a small bowl; whisk until homogenous and refrigerate.
Season the ground beef with sea salt and black pepper.
Heat a cast-iron skillet or non-stick pan over medium-high heat. Add the beef and cook until fully browned and the internal temperature reaches 160°F (71°C).
Distribute the chopped romaine lettuce evenly across four large serving bowls.
Arrange cherry tomatoes, red onion, and dill pickle slices over the lettuce base.
Portion the cooked ground beef into the center of each bowl.
Top each bowl with avocado slices and drizzle with the prepared special sauce immediately before serving.