Upgrading to CTools 3.10.0 and/or various Symfony upgrades can break the simple task of adding content on your Drupal site.

Drupal\Component\Plugin\Exception\ContextException: The context is not a valid context. in Drupal\Core\Executable\ExecutablePluginBase->getContextDefinition() (line 184 …

Update:  Seems confirmed this is CTools, see critical bug issue.

And this fixed it:

git revert 0fbbbaf
[main 7be1cd2] Revert fatal error standard code update "Update composer lock"
 1 file changed, 163 insertions(+), 220 deletions(-)
saharareporters [main]$ dco install # that is, composer install - dco is my alias for ddev composer
Gathering patches for root package.
Installing dependencies from lock file (including require-dev)
Verifying lock file contents can be installed on current platform.
Warning: The lock file is not up to date with the latest changes in composer.json. You may be getting outdated dependencies. It is recommended that you run `composer update` or `composer update <package name>`.
Package operations: 0 installs, 27 updates, 1 removal
  - Removing drupal/entityqueue (1.2.0)
Deleting web/modules/contrib/entityqueue - deleted
Gathering patches for root package.
Gathering patches for dependencies. This might take a minute.
  - Downgrading drupal/core-composer-scaffold (9.4.4 => 9.4.3): Extracting archive
  - Downgrading symfony/yaml (v4.4.44 => v4.4.43): Extracting archive
  - Downgrading symfony/translation (v4.4.44 => v4.4.41): Extracting archive
  - Downgrading symfony/event-dispatcher (v4.4.44 => v4.4.42): Extracting archive
  - Downgrading symfony/dependency-injection (v4.4.44 => v4.4.43): Extracting archive
  - Downgrading symfony/console (v4.4.44 => v4.4.43): Extracting archive
  - Downgrading symfony/filesystem (v5.4.11 => v5.4.9): Extracting archive
  - Downgrading symfony/config (v4.4.44 => v4.4.42): Extracting archive
  - Downgrading symfony/css-selector (v5.4.11 => v5.4.3): Extracting archive
  - Downgrading symfony/dom-crawler (v4.4.44 => v4.4.42): Extracting archive
  - Downgrading symfony/browser-kit (v4.4.44 => v4.4.37): Extracting archive
  - Downgrading symfony/finder (v6.1.3 => v6.1.0): Extracting archive
  - Downgrading symfony/validator (v4.4.44 => v4.4.43): Extracting archive
  - Downgrading symfony/serializer (v4.4.44 => v4.4.43): Extracting archive
  - Downgrading symfony/routing (v4.4.44 => v4.4.41): Extracting archive
  - Downgrading symfony/mime (v5.4.11 => v5.4.10): Extracting archive
  - Downgrading symfony/http-foundation (v4.4.44 => v4.4.43): Extracting archive
  - Downgrading symfony/process (v4.4.44 => v4.4.41): Extracting archive
  - Downgrading symfony/var-dumper (v5.4.11 => v5.4.9): Extracting archive
  - Downgrading symfony/debug (v4.4.44 => v4.4.41): Extracting archive
  - Downgrading symfony/error-handler (v4.4.44 => v4.4.41): Extracting archive
  - Downgrading symfony/http-kernel (v4.4.44 => v4.4.43): Extracting archive
  - Downgrading drupal/migmag (1.8.1 => 1.8.0): Extracting archive
  - Downgrading symfony/string (v6.1.3 => v6.1.2): Extracting archive
  - Downgrading drupal/noreferrer (1.14.0 => 1.13.0): Extracting archive
  - Downgrading drupal/ctools (3.10.0 => 3.9.0): Extracting archive
  - Downgrading symfony/mailer (v5.4.11 => v5.4.10): Extracting archive

And a drush cache-reload, of course.

Full error, for search engines:

The website encountered an unexpected error. Please try again later.

Drupal\Component\Plugin\Exception\ContextException: The context is not a valid context. in Drupal\Core\Executable\ExecutablePluginBase->getContextDefinition() (line 184 of core/lib/Drupal/Core/Plugin/ContextAwarePluginTrait.php).

Drupal\Core\Executable\ExecutablePluginBase->getContext(NULL) (Line: 116)
Drupal\Core\Executable\ExecutablePluginBase->getContextValue(NULL) (Line: 91)
Drupal\Core\Entity\Plugin\Condition\EntityBundle->evaluate() (Line: 77)
Drupal\Core\Condition\ConditionManager->execute(Object) (Line: 84)
Drupal\Core\Condition\ConditionPluginBase->execute() (Line: 376)
Drupal\pathauto\Entity\PathautoPattern->applies(Object) (Line: 320)
Drupal\pathauto\PathautoGenerator->getPatternByEntity(Object) (Line: 41)
Drupal\pathauto\PathautoWidget->formElement(Object, 0, Array, Array, Object) (Line: 353)
Drupal\Core\Field\WidgetBase->formSingleElement(Object, 0, Array, Array, Object) (Line: 220)
Drupal\Core\Field\WidgetBase->formMultipleElements(Object, Array, Object) (Line: 111)
Drupal\Core\Field\WidgetBase->form(Object, Array, Object) (Line: 181)
Drupal\Core\Entity\Entity\EntityFormDisplay->buildForm(Object, Array, Object) (Line: 121)
Drupal\Core\Entity\ContentEntityForm->form(Array, Object) (Line: 127)
Drupal\node\NodeForm->form(Array, Object) (Line: 106)
Drupal\Core\Entity\EntityForm->buildForm(Array, Object)
call_user_func_array(Array, Array) (Line: 531)
Drupal\Core\Form\FormBuilder->retrieveForm('node_article_form', Object) (Line: 278)
Drupal\Core\Form\FormBuilder->buildForm(Object, Object) (Line: 97)
Drupal\autosave_form\Form\AutosaveFormBuilder->buildForm(Object, Object) (Line: 73)
Drupal\Core\Controller\FormController->getContentResult(Object, Object)
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 564)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 124)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 158)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 80)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 709)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)