Duplicar Model com relação e relação da relação

DuplicateProducService.php

<?php
   public function duplicate(Product $product)
    {
        $this->authorize('duplicateProduct', $product);

        $newProduct = $product->replicate();
        $newProduct->name = $product->name . " [Cópia]";
        $newProduct->save();

        $product->load('variations.items');

        $items = [];

        foreach ($product->variations as $variation) {
            $newProduct->variations()->create([
                'name'      => $variation->name,
                'limit_min' => $variation->limit_min,
                'limit_max' => $variation->limit_max,
                'ranking'   => $variation->ranking,
            ]);

            foreach ($variation->items as $item) {
                $items[] = [
                    'key'     => $variation->name,
                    'name'    => $item->name,
                    'ranking' => $item->ranking,
                    'amount'  => $item->amount
                ];
            }
        }

        $newProduct->load('variations.items');

        $itemsCollection = collect($items);

        foreach ($newProduct->variations as $newVariation) {
            $itemsToSave = $itemsCollection->where('key', $newVariation->name)->map(function ($item) {
                return [
                    'name'    => $item['name'],
                    'ranking' => $item['ranking'],
                    'amount'  => $item['amount']
                ];
            });

            $newVariation->items()->createMany($itemsToSave);
        }

        return new ProductResource($newProduct);
    }
?>