In a mixing bowl, combine olive oil, minced garlic, lemon juice, dried oregano, thyme, salt, and black pepper. Whisk until well-blended. Coat the sirloin steak in the mixture and cover. Allow it to marinate for at least 30 minutes or up to 4 hours.

Prepare the tzatziki sauce by mixing Greek yogurt, grated cucumber, lemon juice, minced garlic, dill, salt, and black pepper until smooth. Cover and chill in the refrigerator.

Make the vinaigrette by whisking together olive oil, lemon juice, honey, minced garlic, and dried oregano until smooth. Set aside.

Heat a skillet over medium-high heat. Remove the steak from the marinade, allowing excess liquid to drip off. Sear the steak for 4-5 minutes per side. Let it rest before slicing.

Assemble the bowl with the cooked grains base, sliced steak on top, and fresh toppings like cherry tomatoes, cucumber, red onion, and roasted chickpeas. Drizzle with tzatziki sauce and vinaigrette, then garnish with feta and fresh herbs.