Creamy Chimichurri Roast Chicken

Name: Creamy Chimichurri Roast Chicken
Ingredients: 5 garlic cloves; 2½ cups (packed) cilantro leaves with tender stems; 2 cups (packed) parsley leaves with tender stems; ¼ cup red wine vinegar; 1 Tbsp. plus 1 tsp. Diamond Crystal or 2¼ tsp. Morton kosher salt; 1 Tbsp. plus 1 tsp. dried oregano; 2 tsp. crushed red pepper flakes; ¾ cup extra-virgin olive oil, divided; 1 cup plain whole-milk Greek yogurt; 1 3½–4-lb. whole chicken, backbone removed, patted dry; 2 tsp. Diamond Crystal or 1¼ tsp. Morton kosher salt