Change H3 in comments

It should work for both, no matter the post has comments or not.

Could you share the link of your site in question?

Here is a link for a post with comment: https://tri-it-fit.de/motivationsprueche-sport/
And here is one without a comment: https://tri-it-fit.de/fitnessuebung-turkish-get-up/

Let's try the steps below:

1) Disable your cache plugin and clear your cache.

2) Make sure this is the only code you added to your child theme to eliminate conflicts from other codes.

I did both. Cleared the cache, and it is the only code I added.

I can see both of them are working now, no matter there's comment or no comment :)
https://www.screencast.com/t/v1aoby8k1K

Sorry. Now I know what you mean. 😅 Yes the "leave a comment" part is no longer an H3 headline. But the "x thought on.." part is still H3.
In this case I still have a problem with the headline structure because in many articles there is no H2 headline.

That's why I asked for both headlines in the comment section (https://generatepress.com/forums/topic/change-h3-in-comments/#post-1688542)

The topic starter is using a child theme, so this is how he managed to change the H3 tag of the comment title:
https://wp-puzzle.com/docs/basic/change-h3-in-comments-list-and-form.html

If you are not using child theme, try this:

add_filter( 'generate_comments_title_output', function( $output, $comments_title ) {
    return sprintf(
        '<strong class="comments-title">you custom comment title</strong>',
        esc_html( $comments_title )
    );
}, 10, 2 );

Thanks for your help. The last solution is working. :)

Nice!

Glad to hear that :)