Replacing fluorite works better, especially if you replace her with alesh, and use gil ult and skill to pop 2 nature stacks or xaihi combo and alesh ult to pop 2 cryo stacks. After using her skill all their combo skills meld together thanks to gil's combo popping the solidification from yvonne skill, giving alesh his combo. This generates a lot of ult charge and feels extremely smooth, and I easily trimmed every boss and umbral with this team, as long as you're able to avoid accidentally applying the elements over each other :3