Well its not 100% accurate and relies on a well produced background image. But I dont see how the links above could not create such an element:
You can see my dirty workaround here:
https://preview.webflow.com/preview/sandburg?preview=e3eea8fd4ab3fabcdb72d034c5cbc09b
BUT the script relies on the fact, that you structure it like a list. Not as a background image.
Trick is to set a div with overflow:hidden as an outside container. Within that you ll have the list with one list-item holding the background image.
It is not 100% what you ll need but a workaround if there is no better solution out there.
I only used this workflow shown by pixelgeek:
forum.webflow.com/t/how-to-make-parallax-elements-in-webflow/7481