Final Boss for 4th ascendancy

I quit. I am not playing this game until you fix that boss. It's beyond ridiculous to expect a casual player to defeat that boss and to tie your final ascendancy to it ruins the whole damn game.

And no, I didn't just try it once. I have attempted it 20+ times. I have spent a fortune on relics. I have read all the guides. I get through all the way to the final boss fine, usually with over 10K in honour. This last time I had 18k and he just one shot me.

Something weird happened on my last run, I got the 40% less damage affliction and it actually reduced my damage by around 90%-95%. I fought the boss for 6 minutes before he did the mechanic and I ran it in the most optimal route (it was obvious where to start and end) and even with 41% MS I barely even made it to the 2nd last one, forget the last one. I have 41% MS and lost a movement speed check in a game that is meant to be slowed down version of poe 1. Why is there a movement speed check in a boss fight?? Trial of Sekhemas is woeful in it's current state.