Magento 2 Custom PHP code in Admin email template

I have an email template that I’m updating using the Magento admin interface. Essentially what I’m trying to do is get the Order ID, hash it, and send it as part of the email.

I read that PHP short tags can be used in email templates, but all of them render blank when the email is actually sent. Here are a few variations I’ve tried:


        This is a paragraph
        < ?php echo 'Hello World';?>
        
< ?php 'Hello World';?>
        
< ?= 'Hello World';?>

‘Hello World’ is not echoed out in any of these scenarios.

My question is, is it possible to inject PHP code directly into the templates via the admin portal?

Thanks in advance.