I have found no other option than to just create a simple boring website that has a simple message after the transaction is complete. PayPal will return users to this website and it will just say transaction is complete. ( I would have 100% preferred PayPal to just stay on its own transaction is complete page, but looks like I have no choice)
I used 000webhost to create a free website.
I then created an index.php file (a simple text file saved as "index.php") in the file manager when managing my website on 000webhost. I then added the following code to the currently blank file:
<div class="row spo space_top_10" style=" margin: auto;width: 50%;margin-top: 3%;"> <h1>Your Company Name Here</h1> <p>Your transaction has been completed! <br> <br>A receipt for your purchase will be emailed to you.<br> <br> You may log into your account at <a href='https://www.paypal.com'>www.paypal.com</a> to view details of this transaction.<br> <br></p> </div>
I then placed my website url into the return url for PayPal request.
At least now my customers will know the transaction has been completed after the payment goes through.