There is an Android Syncthing fork [1] which is active and 1.3K stars (for whatever that's worth).
[1] https://github.com/Catfriend1/syncthing-android
I've been using that one for a long time now. I recall that when I got started with Syncthing (some months to a year or two ago?), it seemed to have been the folk wisdom to use Syncthing-Fork, but I don't recall what the reason was.