what was the difficulty level?
Armour doesn't matter that much. I had the Mastercrafted Ursine Armour or the Mastercrafted wolven armour (don't remember which I wore for the fight) on.
In death March, two or three shots from him and I'm dead.

I don't block any enemies in witcher mostly. Didn't use blocking here too.
Parrying and countering only.
And drank a ton of decoctions for the fight.
The last two or three fears are the only challenge.
But ofcorse you could beat them without much effort using the heavy attack tier 3 special or maybe the swivel combo.
This is the only fight that was hard for me. I rarely die on a battle and here I died like 8 or 9 times.

I depends on the build I guess.
Maximum death counts as I remember
1. Iris' Greatest Fear - 8 or 9 times
2. Imlerith - about 4 times I guess.
3. Eredin - about 2 or 3 times.
Other than that one shotted mostly every other boss or monstor fight well other than the Archgriffin at white Orchard.
For a much more interesting fight try aggroing them all at once at win

Gonna try that in Death March NG+ when I get the time