How to Remove Parent Category from Breadcrumb of CPT?

Hello,

Thank you for contacting the support and sorry for any inconvenience that might have been caused due to that.

Paste the below filter code inside your active theme’s function.php file.

/**
 * Allow changing or removing the Breadcrumb items
 *
 * @param array       $crumbs The crumbs array.
 * @param Breadcrumbs $this   Current breadcrumb object.
 */
add_filter( 'rank_math/frontend/breadcrumb/items', function( $crumbs, $class ) {
        // check if we are viewing single posts
	if(is_singular('post')){	//replace post with your postype
		//Unset elements with key 1
		unset($crumbs[1]);
                $crumbs = array_values($crumbs);
		return $crumbs; 
	}
	return $crumbs;
}, 10, 2);

I hope that helps. Thank you, and please don’t hesitate to contact us anytime if you need further assistance.