Synchronization of files is very useful, but it can be overwhelmingly complex, too. Cloudron has several applications which sync.
I would like to hear some suggestions on how to go about organizing all the synchronizations. Here are a few layers which I think might need to be considered:
On which Hard Disk (HD), Solid State Drive (SSD) is the file located?
Which devices have access to this file, bearing in mind that some drives are available to several devices, eg. Network Attached Storage (NAS)
Which application is sharing this file, e.g. NextCloud, SyncThing, Shaarli, etc. These different programs have different defaults for storage locations.
Some files might be available through one or more protocols, e.g. HTTP, FTP, Gemini, IPFS, TOR, Bittorrent
Some files you might want to be available only to yourself, whereas others might be made available to different groups, e.g. family, friend, or made public access.
There might be some other layers to consider. I hope somebody has thought about these issues already and has rationalized it. Perhaps there is a good video or some diagrams.