Ah, I am not familiar at all with Windows, so I honestly wouldn’t know. Does the Immich CLI even work on Windows?
But going off by the comments and the parts I understand, I guess it could kinda work, assuming that the arguments are all correct. Although, it will try to upload all photos every time, regardless if Immich already has them or not. Which is not ideal but I believe Immich will filter out duplicated photos. But it’s worth checking if it’s indeed smart enough to do that.
For the Immich command it will upload the files to an album called “Camera_Backup”. Not sure if that’s what you want. If not, then remove the -a flag. If you want to upload it to a specific album, then instead add ‘-A albumname’ (edit: I realize I might be wrong here. If you have multiple folders in Syncthing you’re backing up it will work differently)
The --delete flag is already in there so it should empty the camera_backup folder, but the robocopy will copy every single photo back into it the next run.