How to use an animated spiral as a mask

I’m trying to use a complex shape as a mask to reveal what’s within it. I tried using the Build modifier, but for this complex shape its not working, its just starting from from random vertices.

So I made my curve and animated it and works fine as it animates from starting point to the end point. I tried using it as smart Boolean but its not working, the spheres just disappear. Is there a way I can use this curve as a mask since the animation works well for what I need?

https://streamable.com/4xz1xn