Shortcode to Return Custom Post Type by Category

function x_shortcode($atts){
    ob_start();
    $i = 0;

    $var = shortcode_atts( array('category' => 'x'), $atts );

    $args = array(
        'post_type'      => 'staff-member',
        'posts_per_page' => '-1',
        'publish_status' => 'published',
        'category_name'  => $var['category']
    );

    $query = new WP_Query($args);

    if($query->have_posts()){
        while($query->have_posts()){
            $query->the_post();

            $x = get_field( "x" );
            $xx = get_field( "xx" );
            $xxx = get_the_post_thumbnail( $post_id, 'full' );

            if($i % 3 == 0){ ?>

                <div class="x-row">

            <?php } ?>

            <div class="staff-card">
                <?php echo $xxx; ?>
                <div class="staff-inner">
                    <h3 class="x"><?php the_title(); ?></h3>
                    <p class="xx"><?php echo $x; ?></p>
                    <p class="xxx"><?php echo $xx; ?></p>
                </div>
            </div>

            <?php

            $i++;

            if($i % 3 == 0){ ?>

            </div>

            <?php }

        }

    }
    ?>
    </div>
    <?php
    return ob_get_clean();
}
add_shortcode( 'shortcode-x', 'x_shortcode' );