Looking at this Squarespace article about Code Injection there is a way to edit your "Order Confirmation" page under Setting --> Advanced --> Code Injection
https://support.squarespace.com/hc/en-us/articles/205815908#toc-step-2---add-html-code
Once at the code injection page, Sqaurespace says you can reference the order id by using the variable {orderId}
How do I use this tag in the Code Injection area to suppress the display of the order number on the "Order Confirmation" page?