Pat picanha dry and score fat cap in crosshatch pattern with shallow cuts ½ inch apart. Season generously with salt, pepper, and smoked paprika. Let rest at room temperature for 30 minutes.

In small saucepan over low heat, add avocado oil and minced garlic. Sauté until fragrant and lightly golden, 1–2 minutes. Add honey, soy sauce, Worcestershire, lemon juice, and chili flakes. Stir until honey melts into glossy glaze. Remove from heat and divide in half—one for brushing, one for finishing. Stir parsley into finishing portion.

Set grill for two-zone cooking at 400–425°F. For charcoal, push coals to one side. For gas/pellet, one zone high, one zone medium-low.

Place picanha fat-side down over direct heat for 4–5 minutes to crisp and render fat until golden and bubbling. Flip.

Move picanha to indirect heat and close lid. Cook until internal temp reaches 125–130°F for medium-rare. Brush with garlic honey chili oil every 5 minutes for lacquered finish.

Remove from grill, tent loosely with foil, and rest 10 minutes.

Slice against the grain into thick strips. Drizzle with remaining clean chili oil before serving.