I am new to object orientation and am trying to create a shortcode with object orientation techniques so that it is possible to access the link_utm attribute in a template file from the outside. But the attribute where I put it in the shortcode is not working and the output is what I defined in the parameter in the shortcode. How to access this attribute from outside? Below what I have achieved so far.

The output of the shortcode with the attributes is like this: [youlike id_post=’6059,73862′ link_utm=’?utm_campaign=test’]

Class Code

class Shortcode {
    public $attLink = [];

    public function __construct( $utm = '?utm_campaign=recirculacao' ) {

        $this->attLink = $utm;

        add_shortcode('youlike', array($this, 'youCanLike'));
    }
     
    public function youCanLike( $atts ) {
        
        ob_start();

        $value = shortcode_atts( array(
            'id_post' => '',
            'link_utm' => '',
        ), $atts );

        // Checa se existe o valor setado antes de continuar para eliminar bugs
        if ( !$value ['id_post'] )
            return false;

        $post_ids_array = explode(',', $value['id_post']);
        $post_current = get_queried_object_id();

        $exclude = array( $post_current );
        $include = $post_ids_array;

        $args = array(
            'ignore_sticky_posts' => true, // Performance
            'no_found_rows' => true, // Performance
            'post__in'  => array_diff( $include, $exclude ),
            'orderby' => 'date',
            'order' => 'DESC'
        );

        get_template_part( 'global-templates/blocks/block', 'you-can-like', $args );

        return ob_get_clean();  
    }
}
$shortcode = new Shortcode();

Link output in the template file

<a href = "<?php the_permalink(); ?><?php $linkUTM = new Shortcode();echo $linkUTM->attLink; ?>"