How do you disable FancyBox?

Hi there,
Tried to override/ empty it like:

Disable theme’s FancyBox via child theme by overriding JS function “activate_fancybox”

In the Child theme functions, I added:
add_action( ‘save_post’, ‘karasu_save_feature_video’ );

function ishyoboy_activate_fancybox_on_blog_single() {
}

ish.activate_fancybox = function (){
}

In /wp-content/themes/no8/assets/frontend/js/main.js, I tried emptying where Fancybox is.

But it made my site buggy, ie portfolio feature images wont load.

What is the easiest way to disable FancyBox? Im using another lightbox plugin.

Cheers,