kim se young:
i don't think the female lead is strong in DOTS, the female lead always rely on Yoo Si Jin help in every action/ thriller moments (e.g when she almost die, was kidnapped etc.)
Then you can try night light, it has 2 awesome female leads
Also secret forest, but idk if she fits the hardworking category. Same for Signal(korean vs.), awesome female lead.
You can try Mystery Queen but idk if would call her physically strong or hardworking.... but she is awesome....., another example would be Mrs Cop series. Awesome female leads and stories for both seasons.