тут очень много с карточкой товара и импортом.

app/Controllers/CatalogController.php

@@ -84,8 +84,8 @@ final class CatalogController
             ['title' => 'Каталог', 'url' => '/catalog'],
         ];
 
-        if (!empty($product['category_id'])) {
-            $breadcrumbs = $categoryRepository->breadcrumbs((int) $product['category_id']);
+        if (!empty($product['display_category_id'] ?? $product['category_id'] ?? null)) {
+            $breadcrumbs = $categoryRepository->breadcrumbs((int) ($product['display_category_id'] ?? $product['category_id']));
         }
 
         $breadcrumbs[] = ['title' => (string) $product['name']];

app/Repositories/ProductRepository.php

@@ -50,13 +50,21 @@ final class ProductRepository extends BaseRepository
         $placeholders = implode(',', array_fill(0, count($categoryIds), '?'));
         $sql = $this->previewSelectSql(
             'AND (
-                    p.category_id IN (' . $placeholders . ')
-                    OR EXISTS (
+                    EXISTS (
                         SELECT 1
                         FROM product_category_links pcl
                         WHERE pcl.product_id = p.id
                           AND pcl.category_id IN (' . $placeholders . ')
                     )
+                    OR (
+                        p.category_id IN (' . $placeholders . ')
+                        AND (p.legacy_path IS NULL OR p.legacy_path NOT LIKE \'/katalog/product/view/1/%\')
+                        AND NOT EXISTS (
+                            SELECT 1
+                            FROM product_category_links pcl_any
+                            WHERE pcl_any.product_id = p.id
+                        )
+                    )
                 )
              ORDER BY p.sort_order, p.name',
             $limit
@@ -74,9 +82,23 @@ final class ProductRepository extends BaseRepository
     public function findBySlug(string $slug): ?array
     {
         $statement = $this->pdo()->prepare(
-            'SELECT p.*, c.name AS category_name, c.slug AS category_slug
+            'SELECT
+                p.*,
+                COALESCE(linked_c.id, c.id) AS display_category_id,
+                COALESCE(linked_c.name, c.name) AS category_name,
+                COALESCE(linked_c.slug, c.slug) AS category_slug
              FROM products p
              LEFT JOIN categories c ON c.id = p.category_id
+             LEFT JOIN categories linked_c
+                ON linked_c.id = (
+                    SELECT pcl.category_id
+                    FROM product_category_links pcl
+                    INNER JOIN categories lc ON lc.id = pcl.category_id
+                    WHERE pcl.product_id = p.id
+                      AND lc.is_active = 1
+                    ORDER BY lc.parent_id IS NULL, pcl.sort_order, pcl.category_id
+                    LIMIT 1
+                )
              WHERE p.slug = :slug
                AND p.is_published = 1
                AND p.is_available = 1