Is there a way to sync my devices locally without iCloud?

I live in a very rural area with equally poor internet. Most of the time my internet and/or cellular service suffices enough to allow me and my family to sync our devices with each other but having to manually enter events, reminders, notes, and etc... into my calendar and family member's calendars is not an uncommon occurrence.

I recently had the thought while having to manually enter a family appointment into a few phones that it would be fantastic if our family Mac could double as a sort of sync server for the local network.

Is that, or something similar, currently a functionality within MacOS?