Ways to improve my Crackling Lance Elementalist?

https://pobb.in/-8wpG-Y_O02b

Hi everyone, I needed some advice on the ways to further improve my DPS as a Crackling Lance Elementalist. You can check the pobb link above.

My main goal is to kill UBERS within 3 seconds, without having them entering second phase. I also struggle against 100% Deli unique bosses.

Although I know there are still a few item upgrades to min-max my DPS, ie Wands and Rings upgrade with synthesized mod, use a Bottled Faith flask, or change the Ascendancy points to use Convergence. But I feel like I have hit a wall because those were only a small DPS increase.

Do anyone know if there are any other ways that can further my upgrades without changing most of my items?

Thank you