I watched Who rules the world recently and I absolutely love the female lead. She is smart, understanding and strong. She didn't focus much on romance till later episodes and even then she prioritises other important things before romance. I would like a Cdrama with such a female lead who is no less stronger than any of the other characters and someone who doesn't fall in love at all.
My recommendations:
The Message - Smart FL, not much romance.
Young Blood - Smart FL and ML form the perfect team. There's romance, but it's not the main focus.
Who Is the Murderer - No romance, FL is okayish smart, but the story is more focused on the ML.