Fix My Build: Ancestral Warchief CHieftain

Hey guys, I've been picking this build based on highest dps in poe.ninja (Tukohama_My_Ngamahu [QUPE888])

I got 6k HP, caped res, good armor on every pieces, but I still get OS by almost everything in this game.
What is wrong ?

What I know: last ascendancy to do, 1% in cold res, and... dunno what else.

Your gear isnt great but besides that:

Your Fire resist is your lowest resist so Wise oak doesnt do anything.
You have no defensive layers at all, you just have a little bit of life.
No fortify and no endurance charges, low armour, phys reduction, evasion, MINUS 48 chaos res. Even still you still only use damage flasks.

What do you expect?

Advices not just comment.

Anyways thanks for the Wise oak I didn't see that.
Took Arohongui and Tasalio acendancies wich both made me more tanky.