Synching iPhone Calendar (or 3rd party calendar) w/ Syncthing or Mobius?

From what I have read so far, it appears that because Apple’s calendar that comes with its devices has its files inaccessible through its files app, there’s no way to specify which app files to sync across devices.

I want to avoid using iCloud to sync the Apple calendar across devices. A way around that appears to be by using iTunes to manually sync across devices. If I have a Mac, iPad and iPhone, this means plugging 2 of the 3 devices into the other, so they are all in sync. Every time I make an update and want the change reflected on other devices, I’d have to manually connect them to sync via iTunes. Pretty cumbersome.

Was hoping Mobius would somehow enable me to sync Apple Calendar, but maybe it has the same limitations as Syncthing in this regard.

That leaves me with considering 3rd party Calendar apps that support iOS, iPadOS, and MacOS, which have files that show up in Apple’s file manager in order to specify the files to sync, and I assume they would have to be the same across all devices to sync properly. If the structure/content of the files differ some how, I’d imagine that syncing would not work.

Is there any way to sync Apple Calendar without iCloud or iTunes?

If not, is there a 3rd party Calendar app that can? I need one that has Travel Time ability, like the Apple Calendar does.

Not an expert, but there’s a reason Apple’s ecosystem is called a “walled garden” :wink:.

What I’d suggest as an alternative is to run a basic CalDAV server on one of your computers and then connect the phone to it. It’s got its drawbacks, but I doubt you’ll find any solution that can actually utilise sync based on local files. I personally use Radicale for this, and if you search for “radicale ios” on Google, there seem to be quite a few answers on how to connect an iOS device to a Radicale server. Radicale itself is a free and open source software, and it’s very easy to run on a desktop machine.