It will post as a new post at the end of the thread. It won't restore at its original location.
It's true, but you can tell anyone it's an old post that you shouldn't be deleting. I wouldn't think it's a big deal to you if you really want that post back unless the thread has been locked by the author.
I'm not sure if you're having trouble deleting the current post incorrectly, but if it does then you can try what these guys suggest.
We do have an warning message before deleting the post if I am not wrong which is enough and that is what followed even on the most updated platforms as well so if we need that undo feature then admin may add but definitely it will not be in his priority list of to do list.
That reminder should already be able to help users to consider deletion carefully so do not delete posts carelessly.