WordPress 5.8 : show new widget

I’ve began a brand new web site with the latest WordPress 5.8.

I’ve made a brand new widget because of the brand new widget builder which use Gutenberg block.

In my capabilities.php

register_sidebar(
    array(
        'identify'          => esc_html__( 'Entête de la web page d'accueil', 'area' ),
        'id'            => 'head-homepage',
        'before_widget' => '<part id="%1$s" class="widget %2$s">',
        'after_widget'  => '</part>',
        'before_title'  => '<h2 class="widget-title">',
        'after_title'   => '</h2>',
    )
);

The template : sidebar-head-homepage.php

If I take advantage of this : <?php get_sidebar('head-homepage'); ?>, the template known as, however by default it is empty (obvioulsy, cuz the file is empty…) and $args* is empty

If I take advantage of this : <?php get_sidebar('head-homepage'); ?>, information from my widget is rendered, however the template will not be callded.

So now, the best way to name my widget appropriately, in order that I can use variables so as to add some CSS on it ?