Server Component (Duplicati.Server.exe)

There are at least a few Docker images with Duplicati already:
https://hub.docker.com/r/intersoftlab/duplicati/
https://hub.docker.com/r/linuxserver/duplicati/

Maybe you can use them “as-is” or as a starting point.

The idea is that Duplicati.Server.exe is the raw service, which can be used with things like Windows service, or systemd because they restart the server automatically if it crashes.
The Duplicati.Service.exe program starts Duplicati.Server.exe and pings it periodically to see if it is responding. Should it stop responding, it will be restarted automatically.