Thank you for the very quick answer! I don't want to display the link on front end, but on the edit post / user relationship metabox.
Maybe I didn't understood your answer, I am not a dev, sorry. And I would understood if this this question is beyond the scope of your support.
OK. I guess is the same for my other post related to metabox relationship custom fields.
FYI pods relationship feature adds a simple edit link near to the related items once selected. A similar solution would be nice.