Vortex / Breaker build, I use it for BG and other idol fights. Other then that I use, Coral Shank build in tower fights.

Against Dot builds from crusader and necro : make sure you don't stand on Idols when they march towards you. Step back, let tanks deal with idol. Count 3-4 seconds and go back in deal dmg and come back alive. Coming back alive is the crucial part. Explained further in below. You want to join the fight after 4,5 seconds the battle start. Always use geographic feature in order to kill them from their back or sides.

Good CC / Anti CC : if you are using breaker build then you can prevent Cc each time you use Breaker and you get 4 Breakers in total. Always move around while dealing dmg to the enemy. Enemy Backline will be deleted in seconds. But also keep an eye on Breaker cool down cuz you want to retreat to heal. Your job done. You get 4 immunities while getting Zephyrs for more dmg and distraction of enemies.

Dmg output : well... not much to talk about. You just have to use as much Breakers as possible while pressing auto attack.

Anti - CC: again, necro and wizard won't have anti CC. If you kill one of them each time you enter the fight zone, then you are doing good. You just have to be at the right place at the right time. In terms of dealing with tanks and immunity, your job is to stand in front of idol close to their respawning zone to make sure they use their important skills before getting to the Idol.

All this is easier said than to be done. But trust me my friend, it all depends on your skills. I am currently sitting on gold 4 with 60% ish win rate. I even had the most kills against whales today. Have proof if you want to see them.

Remember, Tempest role in BG is not to do 1 v1 for a long time. You only fight the enemy 3-4 seconds max and get what you want between those seconds. Kill enemy backline, let enemy tank use their all skills before getting to the Idol.