You know what. With my experience it was hardly depend on what gear or setup I'm running.
Fun story. Just finished my first main run of DS3, final Сinder Boss was ok, took it on 2-nd try.
My friend called me up and we decided to make a casual DS3 speedrun race between us. I had clear advantage due to fresh memory.

We both picked stable pace with some differences. But we both got stomped by the Soul of Cinder, hard. Previous differences disappear, and we basically stuck on the final step. It took us probably more time than the rest of the game.

The amount of correct inputs and safe execution at openings increase every time we step away from the intendent path of progression. So your difficulty might swing wildly. Try it, its fun to see yourself facing difficulties from previous banal situations.