comments on blog page

the whole article is shown (not only a excerpt)

You may need to start customising your theme’s template files – possibly via a child theme. Have you tried using the <!--more--> tag in your post’s content?

i would like to show the comments and comment form also on the blog page

The standard behaviour in most themes is to show comments and the comment form on the single post page only. Changing this behaviour may involve extensive theme editing and coding.

Your theme’s index.php template file may be using <?php the_excerpt();?> instead of <?php the_content();?> in its template files. Try creating a child theme, editing the relevant template file(s) in your child and replacing <?php the_excerpt();?> with <?php the_content();?>.

by default, the comments are only shown on ‘singular’ pages, i.e. single posts and static pages.

overwriting this is not recommended and might cause problems as many functionalities of ‘wp_list_coments()’ do not work properly on index pages.

general:

add this into the loop of the index template (in a child theme?) where you want to show the commments and comment form:

<?php gloabal $withcomments; $withcomments = 1; comments_template(); ?>