diff --git a/src/Plugin/Validation/Constraint/UserMailUniqueDbeeValidator.php b/src/Plugin/Validation/Constraint/UserMailUniqueDbeeValidator.php
index ab579a8..f947f0e 100644
--- a/src/Plugin/Validation/Constraint/UserMailUniqueDbeeValidator.php
+++ b/src/Plugin/Validation/Constraint/UserMailUniqueDbeeValidator.php
@@ -14,7 +14,7 @@ class UserMailUniqueDbeeValidator extends UniqueFieldValueValidator {
   /**
    * {@inheritdoc}
    */
-  public function validate($items, Constraint $constraint): void {
+  public function validate(mixed $items, Constraint $constraint): void {
 
     if (!$constraint instanceof UserMailUniqueDbee) {
       throw new UnexpectedTypeException($constraint, UserMailUniqueDbee::class);
diff --git a/tests/src/Functional/DbeeAdminPeopleTest.php b/tests/src/Functional/DbeeAdminPeopleTest.php
index d261fc2..41be5e4 100644
--- a/tests/src/Functional/DbeeAdminPeopleTest.php
+++ b/tests/src/Functional/DbeeAdminPeopleTest.php
@@ -2,6 +2,9 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
+
 /**
  * Search a user from admin/people page.
  *
@@ -9,6 +12,8 @@ namespace Drupal\Tests\dbee\Functional;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeAdminPeopleTest extends DbeeWebTestBase {
   /**
    * User with different name than the one in the mail.
diff --git a/tests/src/Functional/DbeeAllUsersBatchTest.php b/tests/src/Functional/DbeeAllUsersBatchTest.php
index 5944d0d..615001a 100644
--- a/tests/src/Functional/DbeeAllUsersBatchTest.php
+++ b/tests/src/Functional/DbeeAllUsersBatchTest.php
@@ -2,6 +2,9 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
+
 /**
  * Enable/uninstall dbee module, Encrypting/Decrypting using batch.
  *
@@ -9,6 +12,8 @@ namespace Drupal\Tests\dbee\Functional;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeAllUsersBatchTest extends DbeeAllUsersTest {
   /**
    * Number of basic users to create.
diff --git a/tests/src/Functional/DbeeAllUsersManyTest.php b/tests/src/Functional/DbeeAllUsersManyTest.php
index c16a06c..bae78d4 100644
--- a/tests/src/Functional/DbeeAllUsersManyTest.php
+++ b/tests/src/Functional/DbeeAllUsersManyTest.php
@@ -2,6 +2,9 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
+
 /**
  * Enable/uninstall dbee module, Encrypting/Decrypting but for a lot of users.
  *
@@ -9,6 +12,8 @@ namespace Drupal\Tests\dbee\Functional;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeAllUsersManyTest extends DbeeAllUsersTest {
 
   /**
diff --git a/tests/src/Functional/DbeeAllUsersTest.php b/tests/src/Functional/DbeeAllUsersTest.php
index 4171e82..7e0d105 100644
--- a/tests/src/Functional/DbeeAllUsersTest.php
+++ b/tests/src/Functional/DbeeAllUsersTest.php
@@ -2,6 +2,9 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
+
 /**
  * Enable/uninstall dbee module, Encrypting/Decrypting all existing users.
  *
@@ -10,6 +13,8 @@ namespace Drupal\Tests\dbee\Functional;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeAllUsersTest extends DbeeWebSwitchTestBase {
 
   /**
diff --git a/tests/src/Functional/DbeeChangeEncryption.php b/tests/src/Functional/DbeeChangeEncryption.php
index 4415b8c..1aa546b 100644
--- a/tests/src/Functional/DbeeChangeEncryption.php
+++ b/tests/src/Functional/DbeeChangeEncryption.php
@@ -4,6 +4,8 @@ declare(strict_types=1);
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
 use Drupal\key\Entity\Key;
 use Drupal\user\Entity\User;
 
@@ -12,6 +14,8 @@ use Drupal\user\Entity\User;
  *
  * @group config
  */
+#[Group('config')]
+#[RunTestsInSeparateProcesses]
 class DbeeChangeEncryption extends DbeeWebTestBase {
 
   /**
diff --git a/tests/src/Functional/DbeeContactMailTest.php b/tests/src/Functional/DbeeContactMailTest.php
index 2f4b13d..ade2dd0 100644
--- a/tests/src/Functional/DbeeContactMailTest.php
+++ b/tests/src/Functional/DbeeContactMailTest.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
 use Drupal\Core\Test\AssertMailTrait;
 
 /**
@@ -11,6 +13,8 @@ use Drupal\Core\Test\AssertMailTrait;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeContactMailTest extends DbeeWebTestBase {
   use AssertMailTrait;
 
diff --git a/tests/src/Functional/DbeeCoreFunctionsTest.php b/tests/src/Functional/DbeeCoreFunctionsTest.php
index ba1171d..451d68c 100644
--- a/tests/src/Functional/DbeeCoreFunctionsTest.php
+++ b/tests/src/Functional/DbeeCoreFunctionsTest.php
@@ -2,6 +2,9 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
+
 /**
  * Check : loading user by id, by email, loading current user, saving user.
  *
@@ -10,6 +13,8 @@ namespace Drupal\Tests\dbee\Functional;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeCoreFunctionsTest extends DbeeWebSwitchTestBase {
   /**
    * User to load.
diff --git a/tests/src/Functional/DbeeEditUserTest.php b/tests/src/Functional/DbeeEditUserTest.php
index 2a85097..3c32843 100644
--- a/tests/src/Functional/DbeeEditUserTest.php
+++ b/tests/src/Functional/DbeeEditUserTest.php
@@ -2,6 +2,9 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
+
 /**
  * Edit users.
  *
@@ -9,6 +12,8 @@ namespace Drupal\Tests\dbee\Functional;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeEditUserTest extends DbeeWebTestBase {
   /**
    * Edited user account.
diff --git a/tests/src/Functional/DbeeEncryptStringTest.php b/tests/src/Functional/DbeeEncryptStringTest.php
index 41760d3..9337132 100644
--- a/tests/src/Functional/DbeeEncryptStringTest.php
+++ b/tests/src/Functional/DbeeEncryptStringTest.php
@@ -2,6 +2,9 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
+
 /**
  * Encryption/Decryption.
  *
@@ -9,6 +12,8 @@ namespace Drupal\Tests\dbee\Functional;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeEncryptStringTest extends DbeeWebTestBase {
   /**
    * {@inheritdoc}
diff --git a/tests/src/Functional/DbeeMailLoginTest.php b/tests/src/Functional/DbeeMailLoginTest.php
index 06e9168..153ec1b 100644
--- a/tests/src/Functional/DbeeMailLoginTest.php
+++ b/tests/src/Functional/DbeeMailLoginTest.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
 use Drupal\user\Entity\User;
 
 /**
@@ -12,6 +14,8 @@ use Drupal\user\Entity\User;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeMailLoginTest extends DbeeWebTestBase {
 
   /**
diff --git a/tests/src/Functional/DbeeNewUsersTest.php b/tests/src/Functional/DbeeNewUsersTest.php
index df84230..26478dd 100644
--- a/tests/src/Functional/DbeeNewUsersTest.php
+++ b/tests/src/Functional/DbeeNewUsersTest.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
 use Drupal\Core\Url;
 
 /**
@@ -13,6 +15,8 @@ use Drupal\Core\Url;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeNewUsersTest extends DbeeWebTestBase {
   /**
    * Admin user account.
diff --git a/tests/src/Functional/DbeeQueryUsersTest.php b/tests/src/Functional/DbeeQueryUsersTest.php
index 27260d9..5b9c0cc 100644
--- a/tests/src/Functional/DbeeQueryUsersTest.php
+++ b/tests/src/Functional/DbeeQueryUsersTest.php
@@ -2,6 +2,9 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
+
 /**
  * Database queries on user emails.
  *
@@ -9,6 +12,8 @@ namespace Drupal\Tests\dbee\Functional;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeQueryUsersTest extends DbeeWebSwitchTestBase {
   /**
    * User 2.
diff --git a/tests/src/Functional/DbeeSearchUserTest.php b/tests/src/Functional/DbeeSearchUserTest.php
index 3569f6b..f30b261 100644
--- a/tests/src/Functional/DbeeSearchUserTest.php
+++ b/tests/src/Functional/DbeeSearchUserTest.php
@@ -2,6 +2,9 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
+
 /**
  * Search users by email.
  *
@@ -10,6 +13,8 @@ namespace Drupal\Tests\dbee\Functional;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeSearchUserTest extends DbeeWebSwitchTestBase {
 
   /**
diff --git a/tests/src/Functional/DbeeTableSchema.php b/tests/src/Functional/DbeeTableSchema.php
index 276b6fc..a1ba1c9 100644
--- a/tests/src/Functional/DbeeTableSchema.php
+++ b/tests/src/Functional/DbeeTableSchema.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
 use Drupal\user\Entity\User;
 
 /**
@@ -12,6 +14,8 @@ use Drupal\user\Entity\User;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeTableSchema extends DbeeWebTestBase {
 
   /**
diff --git a/tests/src/Functional/DbeeUserResetPassTest.php b/tests/src/Functional/DbeeUserResetPassTest.php
index 4b733fc..ad5b6e5 100644
--- a/tests/src/Functional/DbeeUserResetPassTest.php
+++ b/tests/src/Functional/DbeeUserResetPassTest.php
@@ -2,6 +2,9 @@
 
 namespace Drupal\Tests\dbee\Functional;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
+
 /**
  * User reset password from email.
  *
@@ -9,6 +12,8 @@ namespace Drupal\Tests\dbee\Functional;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeUserResetPassTest extends DbeeWebTestBase {
   /**
    * Edited user account.
diff --git a/tests/src/Kernel/DbeeFromConfig.php b/tests/src/Kernel/DbeeFromConfig.php
index 0a492af..3b7e140 100644
--- a/tests/src/Kernel/DbeeFromConfig.php
+++ b/tests/src/Kernel/DbeeFromConfig.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\Tests\dbee\Kernel;
 
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
 use Drupal\Core\Config\ConfigImporter;
 use Drupal\Core\Config\StorageComparer;
 
@@ -10,6 +12,8 @@ use Drupal\Core\Config\StorageComparer;
  *
  * @group dbee
  */
+#[Group('dbee')]
+#[RunTestsInSeparateProcesses]
 class DbeeFromConfig extends DbeeKernelTestBase {
 
   /**