Give this function a try:
add_action( 'wp','generate_move_blog_page_header' );
function generate_move_blog_page_header()
{
if ( is_home() ) :
remove_action('generate_after_header','generate_page_header', 10);
add_action('generate_before_main_content','generate_page_header', 0);
endif;
}
Adding PHP: https://generatepress.com/knowledgebase/adding-php-functions/