I had this error when upgrading to Drupal 9 (issue is most likely a drush update issue):
PHP Fatal error: Uncaught ArgumentCountError: Too few arguments to function Drush\Log\DrushLog::__construct(), 1 passed in /var/www/html/web/core/lib/Drupal/Component/DependencyInjection/Container.php
Solution:
run the following command (make sure you are in f.e. sites/mysite):
drush sqlq "truncate table cache_container"
This fixes the issue!