Preheat airfryer to 400ºF.

Pat steak dry with paper towels then season with 1 teaspoon salt.

Place steak in air fryer basket and cook until browned and an instant read thermometer inserted in the center registers 120–125ºF for medium-rare or 130–135ºF for medium, 8–12 minutes.

Transfer steak to a plate and tent with foil; let rest 5 minutes.

Preheat a large cast-iron skillet over high for 5 minutes.

Pat steak dry with paper towels, then season with 1 teaspoon salt.

Reduce heat to medium-high. Add a splash of vegetable oil and swirl to coat the pan. Place steak in skillet. Cook until charred and beads of moisture begin to form around edges of steak, about 3 minutes. Flip and continue cooking until an instant-read thermometer inserted in the center registers 125ºF for medium-rare, about 3 more minutes. For medium cook to an internal temperature is 135ºF, about 4 minutes per side.

Transfer steak to a clean plate, tent loosely with foil or parchment paper and let rest 10 minutes.

Turn all burners to high, cover, and let grill preheat for about 15 minutes. Brush grill grate clean.

Pat steak dry with paper towels, then season with 1 teaspoon salt and ½ teaspoon pepper.

When ready to cook, keep primary burner on high and turn other burners off.

Place steak over hot part of grill and cook until beginning to char and beads of moisture appear on edges of steak, 5–6 minutes. Flip steak and continue to cook until an instant-read thermometer inserted in the center registers 125ºF for medium-rare, about 5 minutes.

Transfer steak to a clean plate, tent loosely with foil or parchment paper and let rest 10 minutes.

Whisk together yogurt, blue cheese, buttermilk, vinegar, Worcestershire, ½ teaspoon salt and ¼ teaspoon pepper until thoroughly combined; set aside.

Combine romaine, tomatoes, pickled onions, blue cheese crumbles, and chives in a large serving bowl.

Slice steak against grain and arrange over salad.

Drizzle dressing over top and serve.

Season salad with salt and pepper to taste and serve.