//More use cases and how-to: https://sabrinazeidan.com/wordpress-multisite-global-menu-tips-create-display-customize/

if (in_array(get_current_blog_id(), array(3,4,6,9))){ //display on these subsites only
	switch_to_blog( '1' ); 	//switch to the main site
	if (is_nav_menu(16)){ //make sure that menu exists there
		wp_nav_menu( 
			['menu'            => '16', //grab menu with ID 16
			'menu_class'      => 'sz-global-menu-style', //add class to the output
			]);
	}
	restore_current_blog();	
}