Disable editor in Posts & Pages

function disable_editor_for_selected_post_types() {

    $disabled_post_types = array('post', 'page'); // Liste der zu deaktivierenden Post-Typen

    foreach ($disabled_post_types as $post_type) {

        remove_post_type_support($post_type, 'editor');

    }

}

add_action('init', 'disable_editor_for_selected_post_types');