First, make the marinade for the steaks. Combine, lemongrass, 1/4 cup minced coriander, 2 cloves crushed garlic, soy sauce, 1/4 cup rice vinegar, Shaoxing cooking wine, brown sugar, Worcestershire sauce, and sesame oil in a large, flat bowl and mix until the sugar has dissolved.
Place steaks into the marinade and cover with plastic wrap. Leave in the refrigerator to marinate for 48 hours.
Heat a grill up to temperature. Then, grill each side of the steaks for 6 minutes (12 minutes total for medium rare). Then, transfer the steaks to a cutting board and let rest for 5 minutes.
Meanwhile, make the chimichurri sauce. In a blender, blend 1/4 cup coriander, parsley, Thai basil, sugar, 1/4 cup rice vinegar, and salt & pepper until the sauce is consistent.
To serve, cut steaks into slices and top with chimichurri sauce from the blender.