Thanks.
I’ve checked your site, and to be frank, this is outside of our scope of support as you’re asking us to do effects for the Flickity slider, which is a third-party plugin.
But to help you out and point you in a direction, the main CSS effect involved with the overlay hover animation is this one.
https://gist.github.com/ejcabquina/0ab471e36275deb26297c84397243ebf
I’m not sure how best to apply this on your carousel as your site isn’t using WPSP. It’s best to ask its developer about this.