[Forminator Pro] Enable usage of form variables in email subject

In Forminator Pro forms, I'm able to use form variables like {embed_title} in the email content. They work as expected. But whenever I try to use the same variable(s) in the email subject, they do not output anything and keep showing the variable itself. As a powerful form plugin, I believe this is a crucial requirement for Forminator Pro.

Is there any feasible custom way that I can achieve this with custom code? Please advice.