The option syntax seems to be option=value (not option value), confirmed by some test.
But the most important thing is to get your old config out of Windows.old before it goes away.
EDIT:
I think these are based on the user. You’re not trying to change that, just change DB location.
Perhaps you did a manual migration of those, per directions on how to migrate to a service?
Regardless, if that part is fine, stop the service, uninstall, reinstall with correct option syntax.
Either put your old duplicati-server.sqlite there, start service, and see if it comes up properly,
or if old configs have aged away then start service and import exported configs (if available).