Get all wp_users sort by metakey

You can index each of the arrays and then orderby 1 or both of them using ASC,DESC as per your requirement

    $meta_query_args = array(
        'relation' => 'OR', // Optional, defaults to "AND"
        'no_login' =>array(
        'key'     => 'user_last_login',                 
        'compare' => 'Not Exists'
        ),
        'login' => array(
        'key'     => 'user_last_login',                 
        'compare' => 'Exists'
        )
    );
    $meta_query = new WP_Meta_Query( $meta_query_args );


        $args = array(
            'offset' => $paged ? ($paged - 1) * $number : 0,
            'number' => $number,
            'fields' => 'all',
            'orderby'           => array(
            'login'         => 'ASC'
        ),                   
            'exclude' => array(get_current_user_id()), 

            'meta_query'  =>$meta_query
        );

        $users = get_users( $args );