Found a solution myself. Here is what did it for me:
add_filter( 'the_content', 'example_view_post_content' );
function example_view_post_content() {
echo wp_trim_words( get_the_excerpt(), 15, '...' );
}I use a lot of custom fields within the articles so maybe that was the reason why the content wasn't clearly displayed. I did a workaround using the excerpt instead.
Sorry for my stupid questions but php and wp dev isn't my strongest area.