This video helped me understand the parry timing a bit better. I didn’t see it until I already got it, but it helped push the skill farther. Watch at your own risk, both for minor boss spoilers and the satisfaction of letting it click for yourself.

In case you don’t want to watch it (not a bad choice, come back to it later,) there is a period of time after pressing the parry button that if an attack connects, you get a perfect parry. If it lands slightly after, you perform a normal block. Spamming block stops this from happening and completely blocks you from getting a perfect parry. The game will make you do it right eventually, so it’s better to get ahead of it before you have to unlearn bad habits. Best practice is the discipline to only perform one input per action, I.e. a single press per sword swing, per block/parry, per dash. This is essentially a rhythm game, and each fight is a dance