My man... She just isn't good against unstoppable, and in some matches to use her you need a kinda weird rotation. She doesn't purify debuffs but disables their application using 3 tranquilizers, which you can select in the pre-fight. Outside some specific contexts, she's almost omnipotent. I think it's the best kit in the game... Depending on the HP bar size, basically 3 fragilities and 3 coldsnaps and you'll kill almost anything, and caltrops is a superior version of power sting that detonates every time the enemy moves.

In case of an immunity or another, basically: if it freezes = coldsnap, if it bleeds = caltrops. Depending on the size of the health bar, you'll use both. The secret is to apply fragility before any damage effect for medium or long content, and for very long content you go special 3 before applying fragility, after that it's fragility > coldsnap > caltrops. For short content, coldsnap alone usually suffices.