I believe what you’re referring to with curves is for updating it for an individual animation that could play anywhere in an animation blueprint. What you need to do is create a curve in the animation that you want to alter. Something like this, created in the actual animation file editor.
Then anytime that animation is playing you can access the value of this curve by using a “Get Curve Value” node and plugging that into the Play Rate of the animation like this.
I should say that I would not do it, exactly as I’ve described here and instead set the curve value as a variable that can be bound to playrate, like this.
this allows you to bind the play rate value directly.
This maintains fast path because you aren’t accessing the blueprint call directly and keeps animation performance better.