Common form content

Hi all,
I have been very impressed migrating to grav so far - I have found it easy to set up and work with! I think it is a very well-designed system that strikes a good balance between flexibility and simplicity.

I have some pages with front-end forms that work very well for my needs - functionality is as desired. However, the first ~30% of these forms are identical fields so I’d like to make it common somehow. Do you have any advice on how to do this?

I originally thought about modifying form.fields in my template twig, but is there a better way to do it? Can I somehow include the common parts through the page frontmatter on my form definition? Or would I need to make a plugin for this?

Thanks for your help!