Do you have an existing working freeware-based Windows-hosted automatic
sync setup for all your devices on your home LAN?
o Windows
o Linux
o Android
o iOS

There are a number of private databases you may wish to be common across
your private LAN that you don't want to put on the Internet for reasons of
intelligent design, mostly with respect to basic privacy considerations.
o Calendar ics files
o Password kdbx files
o Contact vcard files
o Truecrypt-style encrypted container files
etc.
https://groups.google.com/d/msg/comp.mobile.android/5HFVXB5yTk4/0vD_ZKkfAQAJ

This problem set would seem to be so common that any decent freeware
solution would likely become a general purpose solution for _any_ common
encrypted file you'd like to sync across your private LAN (e.g., your
medical record numbers, or bank account numbers, or whatever).

Do you have an existing working freeware-based Windows-hosted automatic
sync setup that works on all your devices on your home LAN?