Update: Even with DEF/SPR buff turned off, she won't heal unless your units are below 50% HP and all of her attack spells are useless unless you're lucky enough to land sleep.

Need some advice here because I'm lost trying to work her out.

As a minwu user/abuser, I think it's a good thing she don't heal at 50%+ health because she can only use it 4 times. If you want her not to spam the same buff over and over again, make sure the whole team get the buff on her first attempt to cast it. And you want to pair her with a tank, that's for sure.

Aye, she works best with bruiser and tank builds where they can afford to drop low, she's very strong with Esther.

Her AI requires tuning depending on the map but if played around with she can be really great.

This is what I'm getting at. I'm running her with Esther and Cloud. Even with all ATK spells and def/spr buffs turned off, she prefers to run towards enemies rather than buff them with Lightning ATK/Debuff Res/self activation down.

I don't know what else I can do.

Perhaps You need to lower her bravery 60 or lower. It work for me to prevent missile type unit to move toward enemies. They'll just using buff & wait till enemies in reach range to attack.

Good info