Sending a flattened copy with a Submit button (mailto:) on iPadOS/iOS

I have some PDF forms with a submit button and a couple of email addresses configured in the "mailto:" action of said button. Whenever a person fills out a form and taps on the Submit button, the iPad will open the Mail App, auto-populate the correct email addresses and attach the form. However, the attached form is still fillable and can be edited by the person receiving the form via email.

Is there a way to make it a flattened copy?

Years ago a menu would pop up when pressing the Submit button asking if you wanted to send a flattened copy.