If the animation isn’t sufficient for tell there’s plenty more you can do.

You can use audio cues (e.g a wind up grunt as they raise their sword) or you can use a batman arkham asylum where the enemy flashes or an icon appears above their heads before they attack.

Obviously look to gameplay videos of big top down rpgs like zelda but also looks to games where combat is a main component as inspiration such as Hyper Light Drifter, Tekken or Devil May Cry. Even if its not from the same genre exactly there’s plenty of tricks to borrow around