Update to Contao 4.13 and easy_themes v2/v3 failed

[frontendschlampe]

My update to Contao 4.13 and PHP 8 with easy_themes v2 or v3 could not be finished, because of the following error:

In service_unavailable.html.twig line 4:
                                                                                                                                   
  An exception has been thrown during the rendering of a template ("Warning: Undefined global variable $TL_EASY_THEMES_MODULES").  
                                                                                                                                   

In config.php line 65:
                                                              
  Warning: Undefined global variable $TL_EASY_THEMES_MODULES  

The extension will be installed, but the manager quit on vendor/bin/contao-console contao:maintenance-mode enable

Do you have any hint for me?

[frontendschlampe]

I deleted system/modules/easy_themes, vendor and composer.lock and make an install again with v3 and now it works.