Create a directory in download repository, <your-sub-dir>
Go to Settings > WP Original Media Path
check Activate that if you are aware of what you are doing.
Change Store uploads in this folder to /data/repository/<your-project>/<your-sub-dir>
Change Full URL path to files to https://download.tuxfamily.org/<your-project>/<your-sub-dir>
Example:
My project on Tuxfamily is called smohaorg and I created a subdirectory in download section which is named wordpressmedia, so I have to use the following: