A way to create a tab and insert it after the last tab

TabOrderControl.php

public function getCMSFields(){
    $fields = parent::getCMSFields();
    
    $rootTab = $fields->fieldByName('Root');
    
    $this->extend('updateCMSFields', $fields);
    $tabs = $rootTab->getTabSet();
    $last = $tabs->last()->name;
    
    $rootTab->insertAfter(Tab::create('FoolashTab'), $last);
    
    return $fields;
}