How do you get a dead insta username?

It's so annoying when there is a generic username that I want but is taken by someone who has never posted or barely posts. Even worse, when the username is 'blacklisted' because the user deleted their account with that username so now that username is void. (only instagram does that crap) Instagram says that when this happens, it's impossible for them to retrieve the username. Is this true? I find it hard to believe that instagram doesn't have control of these such usernames on their OWN platform. Like am I right or ami I wrong? I am a person with a very large following and have a big brand and I am looking for a specific generic ig username that is void for everyone. Can someone please possibly guide me along the path I should take to receive a username like this?

You can check out forumkorner to see if there is anybody selling the name you are interested in.
People on that forum usually are selling a good amount of OG usernames

Well, those are the smart ones. Be fast or lose out.