Customizing Category Pages

I want to add some custom content to each category page. The custom content would be placed above the list of posts for that category.

In this thread:
https://generatepress.com/forums/topic/how-to-customize-category-archive-page-layouts/
I found this code:

add_action( 'generate_before_main_content', 'tu_add_content_above_posts', 0 );
function tu_add_content_above_posts() {
    if ( is_category( 'category-name' ) ) : ?>
        Your content
    <?php endif;
}

So, what I did is i modified the archive.php file by adding this:

do_action( 'generate_archive_title' );
/*my edit*/

if ( is_category( 'cat-1' ) ) : ?>
     <div>
	<p>
           Custom content for cat 1.
 	</p>
    </div>
	<?php endif;
if ( is_category( 'cat-2' ) ) : ?>
     <div>
          <p>
             Custom content for cat 2.
          </p>
     </div>
        <?php endif;

/*end my edit*/

This seems to work fine. However, I'd have to create a child theme in order to persist this across an theme update.

Is there a more efficient way to do this? One that would not require a child theme. And perhaps allow for a separate file for each category with it's own custom HTML content?

Thanks,

Hernan