Parallax with aria-label

Hello everyone,
I’m trying to add a parallax effect to some elements on a website I’m developing.

To do so I’m using this thread as a guide: https://generatepress.com/forums/topic/parallax-effect-using-generatepress-theme-and-generateblocks/

Thing is that I wanted to hve different speeds for different elements, so I was wondering if there is a way to customize te “.4” part in

var coords = (scrolled * 0.4) + ‘px’

maybe with an aria-label? So that I can just add the parallax class and then tweak the speed (and direction using negative numbers) of the effect for that specific element.

Otherwise, should I duplicatee the script with a different class for each speed?

Thanks!
Lorenzo