Step 1: First you need to add registration.php file in the following path: app/code/Magemonkey/Orderstatus/

Add below code in it.

<?php
MagentoFrameworkComponentComponentRegistrar::register(
	MagentoFrameworkComponentComponentRegistrar::MODULE,
	'Magemonkey_Orderstatus',
	__DIR__
);

Step 2: Next, you need to add module.xml file in the following path:
app/code/Magemonkey/Orderstatus/etc/

Add below code in it.

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="Magemonkey_Orderstatus" setup_version="1.0.0">
    </module>
</config>

Step 3: Now you need to add Orderstatus.php file in the following path: app/code/Magemonkey/Orderstatus/Cron/

Add below code in it.

<?php

namespace MagemonkeyOrderstatusCron;

class Orderstatus
{
	protected $_logger;
	protected $_orderCollectionFactory;
	protected $orderObj;
	protected $timezoneInterface;
   	
   	public function __construct(
       PsrLogLoggerInterface $logger,
       MagentoSalesModelResourceModelOrderCollectionFactory $orderCollectionFactory,
       MagentoSalesModelOrder $orderObj,
       MagentoFrameworkStdlibDateTimeTimezoneInterface $timezoneInterface
   	) 
    {
     	$this->_logger = $logger;
     	$this->_orderCollectionFactory = $orderCollectionFactory;
     	$this->_orderObj = $orderObj;
     	$this->_timezoneInterface = $timezoneInterface;
    }

	public function execute()
	{
		$paymentMethod = 'stripe_payments_sofort';
		/* get order collection */
		$collection = $this->_orderCollectionFactory->create()->addFieldToSelect('*')
		->addFieldToFilter('status', ['in' => 'pending']);

	     /* join with payment table */
	    $collection->getSelect()
	    ->join(
	        ["sop" => "sales_order_payment"],
	        'main_table.entity_id = sop.parent_id',
	        array('method')
	    )
	    ->where('sop.method = ?',$paymentMethod);

	    /* get current date time */
	    $current_datetime = $this->_timezoneInterface->date()->format('Y-m-d H:i:s');
	    
	    /* set default time in second */
		$set_default_time = 3600;
	    foreach ($collection->getData() as $key => $orders) {
	    	
	    	$created_at = $orders['created_at'];
			$dateTimeZone_order = $this->_timezoneInterface->date(new DateTime($created_at))->format('Y-m-d H:i:s');

			/* get time diff from order datetime and current datetime */
			$time_diff = strtotime($current_datetime) - strtotime($dateTimeZone_order);

			/* change order status to processing */
			if($set_default_time <= $time_diff){
				/* @var $order MagentoSalesModelOrder */
				$order = $this->_orderObj->load($orders['entity_id']);
			    $order->setStatus("processing");
			    $order->save();
			}
	    }
	}
}