Sidebar, custom template and WP_query

Hi all.

I create a my custom page template (page-mycustom.php) and I would like to eliminate the sidebar from this page.

I add this code in function.php (child theme)

add_filter('kadence_display_sidebar', 'kad_custom_fullwidth_page');
function kad_custom_fullwidth_page($sidebar) {
  if (is_page_template('page-blogfullwidth.php')) {
    return false;
  }
  return $sidebar;
}

The code works until you insert a loop in the template.
It seems that a second cycle, the function is no longer considered.

Can you help me?

Thank,
Marco