Possible customization for https://ultraviolet.com/

The following JavaScript and CSS should make it so, when on mobile, that the submenus will open on a click on their respective menu items. We may also need to work on this a bit as it has not been tested on your site.

Reminder: it is always best to test things out on a staging site if possible!

Here’s how to apply JS and CSS to your site …

• How to apply JavaScript: https://www.wpbeginner.com/wp-tutorials/how-to-easily-add-javascript-in-wordpress-pages-or-posts/
• How to apply CSS: https://www.wpbeginner.com/plugins/how-to-easily-add-custom-css-to-your-wordpress-site/

Javascript via php snippet

add_action( 'wp_footer', 'add_ultra_js' );

function add_ultra_js() { ?>
<script>
if ( window.screen.width < 600 ) {
       let ultraNavMenuTwo = document.querySelectorAll( 'li' );
       for ( let i = 0; i < ultraNavMenuTwo.length; i++ ) {
           if ( ultraNavMenuTwo[i].classList.contains('wp-block-navigation-submenu') ) {
        ultraNavMenuTwo[i].firstChild.addEventListener( "click", ultraToggleSubMenuTwo );
        ultraNavMenuTwo[i].style.cursor = "pointer";
           }
       }
    }

    function ultraToggleSubMenuTwo( e ) {
        let ultraNavSubmenuTwo = e.target.nextSibling.nextSibling;
        ultraNavSubmenuTwo.classList.toggle( "active" );
    }
</script>
<?php }

CSS

.ultraOpenSubmenu {
  display: block;
}