Argument 2 passed to Drupal\Console\Command\Test\RunCommand::__construct() must be an instance of Drupal\simpletest\TestDiscovery I'm trying to install drupal console with Drupal 9.0.5, so I ran this command:
composer require drupal/console:~1.0

However when I try run the drupal command with any arguments I get this error:
root@6dc17ce2d4bf:/opt/drupal# drupal --version
TypeError: Argument 2 passed to Drupal\Console\Command\Test\RunCommand::__construct() must be an instance of Drupal\simpletest\TestDiscovery, null given in /opt/drupal/vendor/drupal/console/src/Command/Test/RunCommand.php on line 58 #0 [internal function]: Drupal\Console\Command\Test\RunCommand-&gt;__construct('/opt/drupal/web', NULL, Object(Drupal\Core\Extension\ModuleHandler), Object(Drupal\Core\Datetime\DateFormatter))
#1 /opt/drupal/vendor/symfony/dependency-injection/ContainerBuilder.php(1144): ReflectionClass-&gt;newInstanceArgs(Array)
#2 /opt/drupal/vendor/symfony/dependency-injection/ContainerBuilder.php(618): Symfony\Component\DependencyInjection\ContainerBuilder-&gt;createService(Object(Symfony\Component\DependencyInjection\Definition), Array, true, 'console.test_ru...')
#3 /opt/drupal/vendor/symfony/dependency-injection/ContainerBuilder.php(558): Symfony\Component\DependencyInjection\ContainerBuilder-&gt;doGet('console.test_ru...', 1)
#4 /opt/drupal/vendor/drupal/console-core/src/Application.php(468): Symfony\Component\DependencyInjection\ContainerBuilder-&gt;get('console.test_ru...')
#5 /opt/drupal/vendor/drupal/console-core/src/Application.php(214): Drupal\Console\Core\Application-&gt;registerCommands()
#6 /opt/drupal/vendor/drupal/console-core/src/Application.php(119): Drupal\Console\Core\Application-&gt;loadCommands()
#7 /opt/drupal/vendor/drupal/console/src/Application.php(64): Drupal\Console\Core\Application-&gt;doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#8 /opt/drupal/vendor/symfony/console/Application.php(147): Drupal\Console\Application-&gt;doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#9 /opt/drupal/vendor/drupal/console/bin/drupal.php(89): Symfony\Component\Console\Application-&gt;run()
#10 /opt/drupal/vendor/drupal/console/bin/drupal(4): require('/opt/drupal/ven...')
#11 {main}
TypeError: Argument 2 passed to Drupal\Console\Command\Test\RunCommand::__construct() must be an instance of Drupal\simpletest\TestDiscovery, null given in Drupal\Console\Command\Test\RunCommand-&gt;__construct() (line 58 of /opt/drupal/vendor/drupal/console/src/Command/Test/RunCommand.php).

I don't really understand this error. Any ideas what might cause this?
This is really just kiamlaluno's answer, but they never posted it so I'll just copy it here verbatim:

Drupal Console has not been updated to run on new Drupal versions.
It's even less compatible with Drupal 9, as many classes or methods
have been removed.