How do I call in a category title on a category page in a child theme?

Add a category.php at your child theme. And copy your archive.php.

Use <?php the_archive_title( '<h1>', '</h1>' ); ?> above the post querry.

If you want to add the archive title to all archives, you can directly create an archive.php in your child theme and add the h1 archive-title at your archive.php.

Check <?php the_archive_title(); ?>