The LinuxServer.io team provides a Qbittorrent image that allows the Qbittorrent client WebUI to be served. However, it doesn't come with a file server, so if hosted remotely, there's no way to retrieve the downloaded files. The image provided here adds a simple HTTP file server to that image.
Please refer to the Usage section of the original Qbittorrent image. The only difference is that this image is at ghcr.io/spacepotahto/qbittorrent:<VERSION>, and port 5000 should also be exposed to allow access of the file server at <your-ip>:5000.