Can you sync automatically photos/videos taken from the camera? That's my #1 for Syncthing on Android
My workaround for this has been to install iCloud on a Windows machine which then downloads all the photos from my phone, and Syncthing on Windows monitors the iCloud folder and shares it with a Linux machine that does my backups. A bit convoluted but it works.
[1] https://github.com/icloud-photos-downloader/icloud_photos_do...