When a post is updated acf includes $_POST[‘_acf_post_id’] and you may be able to use this to get the post status. But ACF is unaware of a post being transitioned to publish status.
When saving a post you would also need to look at the standard fields for a post that WP uses an check these to find out if a post is being published.
There are also multiple ways that a post can be published and some of them do not cause a submission of the post. For example you can publish a post from the quick edit menu.
