How to display multiple authors on a WordPress post - php

Question

I have a WordPress blog and some of the articles are written by multiple authors, therefore I would like to display them on the post. Part of the goal has been achieved by installing the Co-Authors Plus plugin. This plugin only allows you to assign more than one author to the post but it won't automatically show both authors on the published post. For that I had to tweak the post-author.php file of my theme Mission News and I helped myself with this guide. I successfully edited the file (as seen in the code below), and now both names, Rachele and Collaboratore are displayed at the end of this post.
The original post-author.php file
<?php if ( get_theme_mod( 'author_box_posts' ) == 'no' ) return; ?>
<div class="post-author">
<?php if ( get_theme_mod( 'author_avatar_posts' ) != 'no' ) : ?>
<div class="avatar-container">
<?php echo get_avatar( get_the_author_meta( 'ID' ), 78, '', get_the_author() ); ?>
</div>
<?php endif; ?>
<div>
<div class="author"><?php the_author(); ?></div>
<p><?php the_author_meta('description'); ?></p>
</div>
</div>
The edited post-author.php file
<?php if ( get_theme_mod( 'author_box_posts' ) == 'no' ) return; ?>
<div class="post-author">
<?php if ( get_theme_mod( 'author_avatar_posts' ) != 'no' ) :
if ( function_exists( 'coauthors_posts_links' ) ) {
coauthors_posts_links();
} else {
the_author_posts_link();
}?>
<div class="avatar-container">
<?php echo get_avatar( get_the_author_meta( 'ID' ), 78, '', get_the_author() ); ?>
</div>
<?php endif; ?>
<div>
<p><?php the_author_meta('description'); ?></p>
</div>
</div>
I suppose the real problem here is my almost non-existent knowledge of php because I failed to correctly edit the content.php file which I believe is the file I need to edit in order to add both author names also in the text right under the title and next to the published date.
The content.php file contains the following lines:
<?php
$author = get_theme_mod( 'post_author_posts' );
$date = get_theme_mod( 'post_date_posts' );
?>
<div <?php post_class(); ?>>
<?php do_action( 'ct_mission_news_post_before' ); ?>
<article>
<?php ct_mission_news_featured_image(); ?>
<div class='post-header'>
<h1 class='post-title'><?php the_title(); ?></h1>
<?php ct_mission_news_post_byline( $author, $date ); ?>
</div>
<div class="post-content">
<?php ct_mission_news_output_last_updated_date(); ?>
<?php the_content(); ?>
<?php wp_link_pages( array(
'before' => '<p class="singular-pagination">' . esc_html__( 'Pages:', 'mission-news' ),
'after' => '</p>',
) ); ?>
<?php do_action( 'ct_mission_news_post_after' ); ?>
</div>
<div class="post-meta">
<?php get_template_part( 'content/post-categories' ); ?>
<?php get_template_part( 'content/post-tags' ); ?>
<?php get_sidebar( 'after-post' ); ?>
<?php get_template_part( 'content/post-author' ); ?>
</div>
<?php get_template_part( 'content/more-from-category' ); ?>
</article>
<?php comments_template(); ?>
</div>
I think I should be editing the <?php ct_mission_news_post_byline( $author, $date ); ?> line, but I don't know how. I tried a few things but none worked.
I would like to be able to display both names of the authors under the title of the post and next to the published date.
Thank you in advance to all those willing to help me.
Have a good day!

Answer 1

This:
(function_exists ('coauthors_posts_links')) {coauthors_posts_links ();}
The other:
{the_author_posts_link (); }