Make the sauce: In a small bowl, whisk mayo, sugar-free ketchup, mustard, relish, vinegar, paprika, and a pinch of salt and pepper. Taste and adjust.
Chill while you cook the turkey.
Prep the bowl base: Rinse and dry the lettuce, then shred or chop. Slice the onions, halve the tomatoes, chop the pickles, and dice the avocado. Set everything aside.
Season the turkey: In a bowl, mix ground turkey with 1/2 tsp salt, black pepper, onion powder, garlic powder, smoked paprika, sugar-free ketchup, mustard, and Worcestershire.
Don’t overmix; just combine evenly.
Cook the turkey: Heat a large skillet over medium-high. Add oil, then the turkey. Break it up with a spatula and cook until browned and no longer pink, about 7–9 minutes.
Taste and add the remaining 1/2 tsp salt if needed.
Melt the cheese: Lower heat to medium-low. Sprinkle the shredded cheddar over the cooked turkey, cover for 1–2 minutes until melted. If using slices, lay them over the turkey and cover just until gooey.
Assemble the bowls: Divide lettuce between bowls.
Top with cheesy turkey, then add tomatoes, pickles, red onion, and avocado.
Add the sauce: Drizzle the special sauce over each bowl. Start with 1–2 tablespoons per serving; add more if you like it saucy.
Finish and serve: Optional final touches: a sprinkle of sesame seeds, extra mustard, or a few jalapeño slices for heat. Serve right away.