Right way to set qty for new products in 2.4.5-p1

I have following code to automatically create products in magento 2.4.5-p1.

<?php
/**
 * Copyright ©  All rights reserved.
 * See COPYING.txt for license details.
 */
declare(strict_types=1);

namespace VendorModuleModel;

use MagentoCatalogModelProduct;
use MagentoCatalogModelProductRepository;
use MagentoCatalogInventoryModelStockItem;

class SaveProduct
{
    /**
     * @var Product
     */
    private $product;

    /**
     * @var ProductRepository
     */
    private $productRepository;

    /**
     * @var Item
     */
    private $stockItem;

    /**
     * SaveProduct constructor.
     * 
     * @param MagentoCatalogModelProduct $product
     * @param MagentoCatalogModelProductRepository $productRepository
     * @param MagentoCatalogInventoryModelStockItem $stockItem
     */
    public function __construct(
        Product $product,
        ProductRepository $productRepository,
        Item $stockItem
    ) {
        $this->product = $product;
        $this->productRepository = $productRepository;
        $this->stockItem = $stockItem;
    }

    /**
     * @throws MagentoFrameworkExceptionCouldNotSaveException
     * @throws MagentoFrameworkExceptionInputException
     * @throws MagentoFrameworkExceptionStateException
     */
    public function execute(array $productsToPatch, array $freeSkusArray,
            $manufacturerId)
    {
        for($i=0; $i<1; $i++) {
        //for($i=0; $i<count($productsToPatch)-1; $i++) {
            $this->product->setAttributeSetId(4);
            $this->product->setTypeId('simple');
            $this->product->setSku($freeSkusArray[$i]);
            $this->product->setName($productsToPatch[$i]['name']);
            $this->product->setPrice(999);
            $this->product->setStatus(1);
            $this->product->setVisibility(0);
            $this->product->setCustomAttributes(
                array(
                    'manufacturer_sku' => $productsToPatch[$i]['sku'],
                    'manufacturer_ean' => $productsToPatch[$i]['ean'], // ignore if null
                    'manufacturer' => $manufacturerId,
                    'manufacturer_name' => $productsToPatch[$i]['name'],
                    'vpe' => $productsToPatch[$i]['vpe'],
                    'umkarton' => $productsToPatch[$i]['umkarton'],
                    'cost' => 999
                )
            );
/*             $this->product->setStockData(
                array(
                    'is_in_stock' => 1, 
                    'qty' => 500
                )
            ); */
            $this->productRepository->save($this->product);
            return $freeSkusArray[$i];
        }
    }
}

Like you can see I commented out “setStockData” thus its a deprecated function.

Now I wonder what is the correct way to set stock for new products?

MagentoCatalogModelProductoffers setQty function, but it has no effect when creating a new product

I also tried with MagentoCatalogInventoryModelStockItem but didnt had success either

Any suggestions or pointing in right direction would be appreciated 🙂

P.S: I only create simple products at the moment