I’m building an accessible dropdown menu and successfully created a button to toggle the menu for screen readers that doesn’t interfere with a top-level link. I targeted the class menu-item-has-children to do this, and thought I was applying it to only one menu, but it’s showing up in the footer where I don’t want or need it. Looking for a way to only apply this in wp_nav_menu when a specific walker is applied.

// ADD SUBMENU BUTTON FOR A11Y
    function test_menu_arrow($item_output, $item, $depth, $args) {
    if (in_array('menu-item-has-children', $item->classes)) {
        $aria_label = $item->title;
        $aria_controls = $item->ID;
        $arrow = '<button class="sub-menu-btn" aria-expanded="false" aria-controls="sub-menu-'.$aria_controls.'" aria-label="More '.$aria_label.'"></button>';
        $item_output = str_replace('</a>', '</a>'. $arrow .'', $item_output);
    }
        return $item_output;
    }
    add_filter('walker_nav_menu_start_el', 'test_menu_arrow', 10, 4);