Sync between devices with all changes

I seem to have issues syncing between devices.

For example, I have this library of contacts that when I edit Category A on my desktop and then on my android edit Category B. When I start Syncthing on both devices, my android overwrites the changes I did in Category A from my desktop.

Is there any way to have it where both versions, from my desktop and android, are merged? I’ve looked everywhere in the documentation for this setting.

Syncthing does cannot merge files, as it has no idea what the file format is.

What does it even mean to merge two different pictures for example?

If the file is concurrently modified on two devices, you would end up with a new conflict file alongside the real file.

Is there a way to specify the file type then, or any other workaround? Can I set it up as though the desktop device is pushed first to the android device and vice versa?

I currently have file versioning so it helps to a degree where I need to manually adjust it after changes haven’t merged.

No, syncthing does not merge files, and will never merge files.

You can adjust folder types so that changes only travel one way.