Hi, I’m not sure if this is what you are looking for but on my end it works great:
add_action( 'init', 'slug_post_type_template' );
function slug_post_type_template() {
$page_type_object = get_post_type_object( 'projects' );
$page_type_object->template = array(
array( 'acf/header', array() ),
array( 'acf/texts', array() ),
array( 'acf/photos', array() ),
);
}
You can check the source on this page:
https://florianbrinkmann.com/en/define-block-templates-5678/