MEGA MENU COLUMNS

maybe you can get comfortable with not having all top-level menu items open with a drop down.
You could, for example, only have one of them open at a time. When you click on another one, the one open menu item closes.

Well enfold provided the option to only show submenu items on hover or on click.

If you choose click we can edit that to only show one toggle open.
then put this to your child-theme functions.php:

function only_one_submenu_open_on_burger(){
?>
<script>
window.addEventListener("DOMContentLoaded", function () { 
  (function($) {
    $('body').on( 'click touch', '.av-active-burger-items > a', function () {
      $(this).parent('li').siblings().removeClass('av-show-submenu');
      $(this).parent('li').siblings().find('ul').slideUp( "fast");
    });
    $('body').on( 'click touch', '.av-active-burger-items .av-width-submenu > a', function () {
      $(this).closest('.sub-menu').siblings().find('li').removeClass('av-show-submenu');
      $(this).closest('.sub-menu').siblings().find('ul').slideUp( "fast");
    });
  })(jQuery);
});
</script>
<?php
}
add_action('wp_footer', 'only_one_submenu_open_on_burger');

after doing that i will have a look to your site to optimize if needed.