For Möbius Sync specific questions, you should ask the developer directly on their own issue tracker. The details should be explained on their website.
As far as logging goes, I don’t think that you can technically disable it right now, but if you set the logfile flag to -, e.g. syncthing -logfile=-, then Syncthing will not save any logs on the disk physically (with the exception of possible panic logs, e.g. after a crash, etc.).