How to get related, upsell & crosssell products in Magento 2

<?php
namespace Mageplaza\HelloWorld\Block;
class HelloWorld extends \Magento\Framework\View\Element\Template
{
    protected $_registry;
    
    public function __construct(
        \Magento\Backend\Block\Template\Context $context,        
        \Magento\Framework\Registry $registry,
        array $data = []
    )
    {        
        $this->_registry = $registry;
        parent::__construct($context, $data);
    }
    
    public function _prepareLayout()
    {
        return parent::_prepareLayout();
    }
    
    public function getCurrentProduct()
    {        
        return $this->_registry->registry('current_product');
    }    
    
}
?>

$myBlock = \Magento\Framework\App\ObjectManager::getInstance()->get('Mageplaza\HelloWorld\Block\HelloWorld');
 
$currentProduct = $myBlock->getCurrentProduct();
 
if ($currentProduct = $myBlock->getCurrentProduct()) {
    $relatedProducts = $currentProduct->getRelatedProducts();
    
    if (!empty($relatedProducts)) {
        echo 'Related Products <br />';    
        foreach ($relatedProducts as $relatedProduct) {
            echo $relatedProduct->getSku() . '<br />';  
            echo $relatedProduct->getName(); //get name
            echo $relatedProduct->getPrice(); //get price
            echo $relatedProduct->getData(); //Show all attributes      
        }
    }    
   
}

$myBlock = \Magento\Framework\App\ObjectManager::getInstance()->get('Mageplaza\HelloWorld\Block\HelloWorld');
$currentProduct = $myBlock->getCurrentProduct();
 
if ($currentProduct = $myBlock->getCurrentProduct()) {
    $upSellProducts = $currentProduct->getUpSellProducts();

    if (!empty($upSellProducts)) {
        echo '<h3>UpSell Products</h3>';
        foreach ($upSellProducts as $upSellProduct) {
            echo $upSellProduct->getSku() . '<br />';        
        }
    }
    
   
}

$myBlock = \Magento\Framework\App\ObjectManager::getInstance()->get('Mageplaza\HelloWorld\Block\HelloWorld');
$currentProduct = $myBlock->getCurrentProduct();
 
if ($currentProduct = $myBlock->getCurrentProduct()) {
    $crossSellProducts = $currentProduct->getCrossSellProducts();

    if (!empty($crossSellProduct)) {
        echo 'CrossSell Products <br />';
        foreach ($crossSellProducts as $crossSellProduct) {
            echo $crossSellProduct->getSku() . '<br />';        
        }
    }
    
   
}