Customize the Author Says text in Genesis comments for Post Author: https://sridharkatakam.com/customize-the-author-says-text-in-genesis-comments-for-post-author/

functions.php

//* Modify the author says text in comments while showing different text for comments made by author that published the post
add_filter( 'comment_author_says_text', 'sk_comment_author_says_text' );
function sk_comment_author_says_text() {
	global $post, $comment;

	if ( $comment->user_id === $post->post_author )  {
		return '- the post author says';
	} else {
		return '- the commentator says';
	}
}

gistfile1.php

//* Modify the author says text in comments
add_filter( 'comment_author_says_text', 'sp_comment_author_says_text' );
function sp_comment_author_says_text() {
	return 'author says';
}