Blog Addon column layout

It should be, try this:

add_filter( 'generate_blog_columns','generate_custom_post_archive_columns' );
function generate_custom_post_archive_columns()
{
    if ( is_post_type_archive( 'my-post-type' ) ) {
        return true;
    }

    return $columns;
}

Adding PHP: https://generatepress.com/knowledgebase/adding-php-functions/

Something like that should work.