Fetching a product in Magento 2 admin backend. This is an alternative to the deprecated Registry class.

CurrentProduct.php

namespace Vendor\CustomModule\Model\Provider;

use Magento\Catalog\Api\Data\ProductInterface;
use Magento\Catalog\Api\ProductRepositoryInterface;
use Magento\Framework\App\RequestInterface;
use Magento\Framework\Exception\NoSuchEntityException;


/**
 * Class Product
 * @package Vendor\CustomModule\Model\Provider
 */
class CurrentProduct
{
    /** @var RequestInterface */
    private $request;
    /** @var ProductRepositoryInterface */
    private $repository;


    /**
     * Product constructor.
     * @param RequestInterface $request
     * @param ProductRepositoryInterface $repository
     */
    public function __construct(
        RequestInterface $request,
        ProductRepositoryInterface $repository
    )
    {
        $this->request = $request;
        $this->repository = $repository;
    }

    /**
     * @return ProductInterface
     * @throws NoSuchEntityException
     */
    public function get(): ProductInterface
    {
        $productId = $this->request->getParam('id');
        $product = $this->repository->getById($productId);

        return $product;
    }
}