Admin-ajax return 0 and error 400 in manager part – WordPress

Here I am facing a problem with the admin-ajax.php of wordpress.

Indeed my project is particular since it contains 2 parts (customer part and admin part). The first part is for the client part since (/wp-content/themes/my_theme_child) is standard.

I have another folder for the admin (/manager/eliteadmin/) and there, impossible to use the standard methods to activate the admin-ajax as I usually do in the functions.php of the child, i.e. something like this for example:

function wpchild_enqueue_styles(){
    wp_enqueue_script('global', get_stylesheet_directory_uri().'/ajax/global.js', array('jquery'), "", true);
    wp_enqueue_script('services', get_stylesheet_directory_uri().'/ajax/services.js', array('jquery'), "", true);
    wp_localize_script('services', 'ajaxurl', admin_url('admin-ajax.php'));
}

here is the structure :

In the part of the manager I try to use ajax, for example:

add_action('wp_ajax_get_citoyens', 'get_citoyens_ajax');
add_action('wp_ajax_nopriv_get_citoyens', 'get_citoyens_ajax');
function get_citoyens_ajax(){
    $context = array();
    $context['response'] = 'ok';
    echo json_encode($context);
    wp_die();
}

js file :

   function display(){
        jQuery.ajax({
            url: ajaxurl,
            type: 'post',
            data: {
                action: 'get_citoyens'
            },
            success: function(context) { 
                var data = JSON.parse(context);
                if(data.response === 'ok') {
                    console.log("it works");
                } 
            },
            error: function(json) {
                console.log('error');
            }
        });
    }

php file :

 var ajaxurl =  "<?php echo admin_url('admin-ajax.php'); ?>";

So obviously in the manager part I can’t use the wp_enqueue_script and wp_localize_script. So my question is the next: how to properly use admin-ajax in this particular context, thank you very much!