.../ckeditor5/src/Plugin/Editor/CKEditor5.php      |  5 ---
 .../tests/src/Functional/ImageUploadTest.php       |  6 +++-
 .../tests/src/Kernel/SmartDefaultSettingsTest.php  |  7 ++++
 .../ckeditor5/tests/src/Kernel/ValidatorsTest.php  | 39 +++++++++++++++-------
 4 files changed, 39 insertions(+), 18 deletions(-)

diff --git a/core/modules/ckeditor5/src/Plugin/Editor/CKEditor5.php b/core/modules/ckeditor5/src/Plugin/Editor/CKEditor5.php
index ab0d03d2c4..c9326b9752 100644
--- a/core/modules/ckeditor5/src/Plugin/Editor/CKEditor5.php
+++ b/core/modules/ckeditor5/src/Plugin/Editor/CKEditor5.php
@@ -12,7 +12,6 @@
 use Drupal\Component\Serialization\Json;
 use Drupal\Component\Utility\NestedArray;
 use Drupal\Core\Cache\CacheBackendInterface;
-use Drupal\Core\Config\Schema\SchemaCheckTrait;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Form\SubformState;
@@ -50,8 +49,6 @@
  */
 class CKEditor5 extends EditorBase implements ContainerFactoryPluginInterface {
 
-  use SchemaCheckTrait;
-
   /**
    * The CKEditor plugin manager.
    *
@@ -729,8 +726,6 @@ public function validateConfigurationForm(array &$form, FormStateInterface $form
     // ::getGeneratedAllowedHtmlValue(), to update filter_html's
     // "allowed_html".
     $form_state->set('ckeditor5_validated_pair', $eventual_editor_and_format);
-
-    assert(TRUE === $this->checkConfigSchema(\Drupal::getContainer()->get('config.typed'), 'editor.editor.id_does_not_matter', $submitted_editor->toArray()), 'Schema errors: ' . print_r($this->checkConfigSchema(\Drupal::getContainer()->get('config.typed'), 'editor.editor.id_does_not_matter', $submitted_editor->toArray()), TRUE));
   }
 
   /**
diff --git a/core/modules/ckeditor5/tests/src/Functional/ImageUploadTest.php b/core/modules/ckeditor5/tests/src/Functional/ImageUploadTest.php
index fdd7235e44..4a93a25d58 100644
--- a/core/modules/ckeditor5/tests/src/Functional/ImageUploadTest.php
+++ b/core/modules/ckeditor5/tests/src/Functional/ImageUploadTest.php
@@ -224,7 +224,11 @@ protected function createEditorWithUpload(array $upload_config) {
             'drupalInsertImage',
           ],
         ],
-        'plugins' => [],
+        'plugins' => [
+          'ckeditor5_imageResize' => [
+            'allow_resize' => FALSE,
+          ]
+        ],
       ],
       'image_upload' => $upload_config,
     ]);
diff --git a/core/modules/ckeditor5/tests/src/Kernel/SmartDefaultSettingsTest.php b/core/modules/ckeditor5/tests/src/Kernel/SmartDefaultSettingsTest.php
index bf294d8375..38defa311c 100644
--- a/core/modules/ckeditor5/tests/src/Kernel/SmartDefaultSettingsTest.php
+++ b/core/modules/ckeditor5/tests/src/Kernel/SmartDefaultSettingsTest.php
@@ -498,6 +498,13 @@ public function test(string $format_id, array $filters_to_drop, array $expected_
 
     // Ensure that the result of ::computeSmartDefaultSettings() always complies
     // with the config schema.
+    // TRICKY: because we're validating using `editor.editor.*` as the config
+    // name, TextEditorObjectDependentValidatorTrait will load the stored filter
+    // format. That has not yet been updated at this point, so in order for
+    // validation to pass, it must first be saved.
+    // @see \Drupal\ckeditor5\Plugin\Validation\Constraint\TextEditorObjectDependentValidatorTrait::createTextEditorObjectFromContext()
+    // @todo Remove this work-around in https://www.drupal.org/project/drupal/issues/3231354
+    $updated_text_editor->getFilterFormat()->save();
     $this->assertConfigSchema(
       $this->typedConfig,
       $updated_text_editor->getConfigDependencyName(),
diff --git a/core/modules/ckeditor5/tests/src/Kernel/ValidatorsTest.php b/core/modules/ckeditor5/tests/src/Kernel/ValidatorsTest.php
index 1f4c8a5327..da7983b645 100644
--- a/core/modules/ckeditor5/tests/src/Kernel/ValidatorsTest.php
+++ b/core/modules/ckeditor5/tests/src/Kernel/ValidatorsTest.php
@@ -580,16 +580,29 @@ public function testPair(array $ckeditor5_settings, array $editor_image_upload_s
       'label' => 'View Mode 2',
     ])->save();
     assert($text_editor instanceof EditorInterface);
-    $this->assertConfigSchema(
-      $this->typedConfig,
-      $text_editor->getConfigDependencyName(),
-      $text_editor->toArray()
-    );
     $text_format = FilterFormat::create([
+      'format' => $text_editor->id(),
+      'name' => $this->randomString(),
       'filters' => $filters,
     ]);
     assert($text_format instanceof FilterFormatInterface);
-
+    // TRICKY: only assert the config schema if we expect NO violations: when
+    // violations are expected, this would just find the very violations that
+    // the next assertion is checking.
+    if (empty($expected_violations)) {
+      // TRICKY: because we're validating using `editor.editor.*` as the config
+      // name, TextEditorObjectDependentValidatorTrait will load the stored
+      // filter format. That has not yet been updated at this point, so in order
+      // for validation to pass, it must first be saved.
+      // @see \Drupal\ckeditor5\Plugin\Validation\Constraint\TextEditorObjectDependentValidatorTrait::createTextEditorObjectFromContext()
+      // @todo Remove this work-around in https://www.drupal.org/project/drupal/issues/3231354
+      $text_format->save();
+      $this->assertConfigSchema(
+        $this->typedConfig,
+        $text_editor->getConfigDependencyName(),
+        $text_editor->toArray()
+      );
+    }
     $this->assertSame($expected_violations, $this->validatePairToViolationsArray($text_editor, $text_format, TRUE));
   }
 
@@ -1062,7 +1075,7 @@ public function providerPair(): array {
       'filters' => [],
       'violations' => [],
     ];
-    $data['INVALID: drupalMedia toolbar item condition NOT met: media filter enabled'] = [
+    $data['INVALID: drupalMedia toolbar item condition NOT met: media filter disabled'] = [
       'settings' => [
         'toolbar' => [
           'items' => [
@@ -1086,13 +1099,17 @@ public function providerPair(): array {
             'drupalMedia',
           ],
         ],
-        'plugins' => [],
+        'plugins' => [
+          'media_media' => [
+            'allow_view_mode_override' => FALSE,
+          ],
+        ],
       ],
       'image_upload' => [
         'status' => FALSE,
       ],
       'filters' => [
-        'filter_html' => [
+        'media_embed' => [
           'id' => 'media_embed',
           'provider' => 'media',
           'status' => TRUE,
@@ -1104,9 +1121,7 @@ public function providerPair(): array {
           ],
         ],
       ],
-      'violations' => [
-        'settings.toolbar.items.0' => 'The <em class="placeholder">Drupal media</em> toolbar item requires the <em class="placeholder">Embed media</em> filter to be enabled.',
-      ],
+      'violations' => [],
     ];
     $data['VALID: HTML format: very minimal toolbar + wildcard in source editing HTML'] = [
       'settings' => [