Welcome to the forum @Teemoe
Duplicati.WindowsService.exe is the program you want. Name is similar. Function is very different.
Migrating from User to Service install on Windows is a How-To about what you’ve been trying to do.
Install Duplicati as a service is a video tutorial on that process.
There are variations possible, and one I strongly suggest is to not use system appdata for Duplicati.
Windows version updates wipe it out. Your databases go to Windows.old but only last for 10 days…