In a medium bowl, whisk together olive oil, coconut aminos, Cajun seasoning, cayenne pepper, salt, lemon pepper, thyme, and rosemary until well combined.

Cut top sirloin into 1-inch cubes and chop bell peppers into similar-sized chunks. Slice onion into wedges.

Combine the steak, bell peppers, and onion with the marinade. Toss to coat evenly and refrigerate for 2 hours or overnight.

Preheat grill to medium heat, around 375°F.

Thread marinated steak and vegetables onto skewers, alternating them.

Grill the kabobs for about 10 minutes, turning every 3 minutes to ensure even cooking.

Brush kabobs with olive oil in the last 2 minutes of grilling. Remove and let rest for a couple of minutes before serving.