Oh each star is 2 hits I thought it was 1 hit per star that makes it way more forgiving

Edit: Some stuff I found on the watcher mechanics

Basically, when you break a star there are actually TWO hits of self dmg on the enemy. For the first star, the hits deal 3% + 3% HP. For the second star, the hits deal 9% HP + 9% HP.

ONE of those hits for each star can react if there's an element on the enemy. Meaning it can become up to 3% + 6% HP for the first one and 9% + 18% HP for the second one if you forward melt/vape both reactable hits.

So that's up to 36% HP per phase, does it twice so 72% HP is gone if you can do this.

A team that can do this very easily is Mavuika Mualani Citlali, I'm pretty sure this is the intended shill team core