did the dead hard nerf really do anything to its pickrate?

You can't use dead hard from a mile away unless you're reacting to a ranged attack, so I don't understand your first point. If you are being chased and the killer catches up to you, they will hit you. You need to use dead hard if you have no other way to prevent them from hitting you, which is often used in conjunction with other defenses such as pallets to force the killer to make a decision at that moment. I'm not talking about drive by dead harding or randomly turning around and running toward the killer, im talking about how the perk is intended to be used: as a last ditch effort to avoid going down when you otherwise would.

You understand this in the second paragraph, which is why im kinda confused where the first statement came from. what do you mean by "cancel dead hard"? its a locked animation interaction wise, you can't drop pallets or anything like that while it is active, nor can you "undo" it. If they mistime it, they are exhausted and gave an animation tell to the killer that they are now defenseless. Thats the exact reason why people sometimes try to pair it with a 360, to hide as much of the animation from the killer as they can to obfuscate the attempt as well as their timing. It doesn't always work, but its an example of why they do it. The risk, again, is that if they don't press it, the killer will M1 them too fast for them to react to and they will be downed.

I think the perk is completely fine in its current state but i absolutely do lament the controller limited killer experience. It feels like you're fighting against damn near everything from the game itself just to play the role, and I can imagine its only worse when console performance issues further compound that fact.

thats not related to the perk? it doesnt need to like make you lose 1k bp every time you use it or slow you for 1 minute or anything like that, it puts you into exhausted which is the same risk any exhaustion perk has: wasting your chance at extending the chase and being punished in a way that prevents another chance for the rest of the chase (presumably)

Yes, and learning it all over again made me realize the new dead hard is much more fun and fits the game better. It and overcome have become my go to exhaustions because I like them and their powerful impact but also they have cost

Overcome requires a healthstate but gives an incredible amount of distance while new dead hard gives a strong option when there weren't any at the cost of tight timing and a mending time sink after that only it and overcome needing healing share