Giving people the ability to delete projects, even their own, could be dangerous.
You could add a true/false field “Delete This post”, then in your acf/save_post filter you could check this field, it it’s set to true then call wp_delete_post() https://developer.wordpress.org/reference/functions/wp_delete_post/
Maybe add a second field as well that has conditional logic to show if the first one is checked “Yes I’m sure I want to delete this”, maybe with some kind of warning that the action cannot be undone.
