Need input for improvements on IMMORTAL CWS Occultist

I saw this vid: https://www.youtube.com/watch?v=1vtqMefQSXM
https://pobb.in/K-a2LBK64zmr

and wanted to try out the immortal build. Unfortunately its not as immortal as the original.

My pob: https://pobb.in/mj_EO-NGzbnE

Sometimes the lifepool drains super fast and i don't know why. Another time it feels like despite being hit there is no recoupe at all. I died a few times now during cowards xp runs - which should be impossible with this build.

The original build is too expansive so i have to work with a tighter budget.
Is someone familiar with the build and can help me to improve it?

Like what would be the next thing to do? Did i miss smth important which bricks the build? How to figure out what causes the life drain?

The endgoal would be the afk uber elder thingy but it feels like i'm miles away.