Radarr / Qbittorrent: How to switch to hardlinks

I always wondered why hardlinks in radarr/ sonarr and qbittorrent didn't work for me. I think the problem was that I mapped the directories as below:

 `

    
    volumes:
      - ./config:/config
      - ./downloads:/downloads
      - ./movies:/movies
`
  

whereas I should've mapped them as:

 `

    
    volumes:
      - ./config:/config
      - ./media:/media 
      - ./media/downloads:/media/downloads
      - ./media/movies:/media/movies
`
  

Now, how do I replace all the duplicate files in /downloads with the links?