Ok, thanks a lot for your insight. I’m not sure why syncthing is run that WAY. Could it be because DietPi keeps logging in the RAM (to avoid the SD card to be written too frequently)?
Anyway:
Running systemctl enable/start/status syncthing-inotify@root.service does not work. It starts but it doesn’t detect any file changes.
Tomorrow I will try changing the service for syncthing to the one provided by upstream, and see if it works. Otherwise I guess I’ll have to ask the DietPi maintainer to fix this.
I’ll report back after the necessary testing. Thanks a lot for your help so far.