Yeah but you can also set it to copy your DCIM photos folder or whatever (if you want to backup files, make it a one way folder sync in the folder options in Syncthing), if Syncthing is limited it is because of Android's filesystem limitations not Syncthing.
Also consider an option that uses termux if Syncthing doesn't work such as this one that uses rsync and termux.
https://howtos.davidsebek.com/android-rsync-termux.html
^the above tutorial may look intimidating at first, but each step is explained very clearly
You can also use termux to install Syncthing and then take advantage of termux's ability to work around Android file system limitations.