diff --git a/mixin/entity-types-php@2.0.0.mixin.php b/mixin/entity-types-php@2.0.0.mixin.php
new file mode 100644
index 0000000..54616e6
--- /dev/null
+++ b/mixin/entity-types-php@2.0.0.mixin.php
@@ -0,0 +1,40 @@
+<?php
+
+/**
+ * Auto-register entity declarations from `schema/*.entityType.php`.
+ *
+ * @mixinName entity-types-php
+ * @mixinVersion 2.0.0
+ * @since 5.73
+ *
+ * Changelog:
+ *  - v2.0 scans /schema directory instead of /xml/schema/*
+ *  - v2.0 supports only one entity per file
+ *  - v2.0 adds 'module' key to each entity
+ *
+ * @param CRM_Extension_MixInfo $mixInfo
+ *   On newer deployments, this will be an instance of MixInfo. On older deployments, Civix may polyfill with a work-a-like.
+ * @param \CRM_Extension_BootCache $bootCache
+ *   On newer deployments, this will be an instance of BootCache. On older deployments, Civix may polyfill with a work-a-like.
+ */
+return function ($mixInfo, $bootCache) {
+
+  /**
+   * @param \Civi\Core\Event\GenericHookEvent $e
+   * @see CRM_Utils_Hook::entityTypes()
+   */
+  Civi::dispatcher()->addListener('hook_civicrm_entityTypes', function ($e) use ($mixInfo) {
+    // When deactivating on a polyfill/pre-mixin system, listeners may not cleanup automatically.
+    if (!$mixInfo->isActive() || !is_dir($mixInfo->getPath('schema'))) {
+      return;
+    }
+
+    $files = (array) glob($mixInfo->getPath('schema/*.entityType.php'));
+    foreach ($files as $file) {
+      $entity = include $file;
+      $entity['module'] = $mixInfo->longName;
+      $e->entityTypes[$entity['name']] = $entity;
+    }
+  });
+
+};
diff --git a/paymentprocessingcore.php b/paymentprocessingcore.php
index c8e2bd5..254634c 100644
--- a/paymentprocessingcore.php
+++ b/paymentprocessingcore.php
@@ -32,6 +32,35 @@ function paymentprocessingcore_civicrm_enable(): void {
   _paymentprocessingcore_civix_civicrm_enable();
 }
 
+/**
+ * Implements hook_civicrm_entityTypes().
+ *
+ * Directly registers entity types to work around a mixin timing issue on
+ * CiviCRM 5.75: the entity-types-php@2 mixin is only loaded for installed
+ * extensions, so during installation the mixin listener is absent and
+ * EntityRepository cannot find our entities. This direct hook ensures entity
+ * types are always registered. When both this and the mixin fire, the result
+ * is identical (same data, same keys).
+ *
+ * @see https://compucorp.atlassian.net/browse/CIVIPLMMSR-623
+ *
+ * @link https://docs.civicrm.org/dev/en/latest/hooks/hook_civicrm_entityTypes
+ */
+function paymentprocessingcore_civicrm_entityTypes(&$entityTypes): void {
+  $schemaDir = __DIR__ . '/schema';
+  if (!is_dir($schemaDir)) {
+    return;
+  }
+  $files = (array) glob($schemaDir . '/*.entityType.php');
+  foreach ($files as $file) {
+    $entity = include $file;
+    if (is_array($entity) && !empty($entity['name'])) {
+      $entity['module'] = E::LONG_NAME;
+      $entityTypes[$entity['name']] = $entity;
+    }
+  }
+}
+
 /**
  * Implements hook_civicrm_container().
  *