optimized version

//Rank Math Breadcrumb
add_filter( 'jnews_breadcrumb', function( $breadcrumbs ) {
    if ( function_exists( 'rank_math_the_breadcrumbs') ) {
        if ( is_single() ) {
            ob_start();
            $breadcrumbs = rank_math_the_breadcrumbs();
            ob_end_clean();
        } elseif ( is_page() or is_category() or is_tag() ) {
            $breadcrumbs = rank_math_the_breadcrumbs();
        }
    }

    return $breadcrumbs;
} );