Insert backlink vs new backlink

Hi there
Is there difference in results between insert backlink in existing post or create new post with backlink? Assume that website has DA40-50.
Thanks

Existing post with a good PA will offer a quicker boost, new post will take time.

Thanks for answer.
Is any harm can be from insert backlinks in existing post or it is same as new posts with backlinks, according Google algorithm? Another words better to do new post with backlink or insert backlink in old post, or it is doesn't matter?
Thanks