+Atk -Def Nephenee

Still very good. If you have the fodder for it, Steady Breath or Close Defense can still give her decent Def. And the Atk boon is very good, she normally has okay-ish attack so she appreciates the buff. With her special Dauntless Lance refine, she still gets more defense and speed when being initiated on, and still takes enough damage to get in the Wrath HP threshold. You should try using her!

How would +atk ever be sub-par? I think you've set your standards too high if anything short of the optimal IVs is below average in your eyes.
This IV is more than average. Like Nyiadae said, Steady Breath and Close defense seal more than make up for the -def.

subpar indeed. Fodding any 5*exclusive skill or investing any amount of dew the onto a 0 merge (whom you don't plan to further merge) is a pathetic way to waste your resource. Even if she's not good, many would appreciate her wrath