No using the internet to sync on Android

I have two smartphone that is Samsung Galaxy A50s and A51. I do not have a wifi connection at home and use a fairly large subscription data quota. I have synced them using mobile hotspot network, is there a way to sync them without an active internet connection? In a sense they stay in sync using a hotspot enabled by one of the devices without using the internet or the internet being turned off.

Thanks

The above sounds as if you have already solved the problem. Is this incorrect? If yes, could you explain in more simple terms what exactly the problem is about and what you’d like to do instead of the hotspot solution?

I synced two Samsung Galaxy A50s and A51 devices using mobile hotspot enabled from one of those devices, but unfortunately, Syncthing doesn’t work if hotspot the device is activated but the data internet connection is turned off. So my question, is there any event for Syncthing to work with hotspot without any internet connection?

Android version? Local discovery is (partly) broken on Android 11+ because the syncthing binary isn’t able to send broadcasts or retrieve local IPs.

Android 11 and OneUI 3.1

The whole hotspot stuff is hairy, you might be able to pull something off to get it to work by hardcoding ips the devices get while in hotspot maybe?