Also, because SAF is so slow on Android for directories containing a large number of files, my personal recommendation would be to not use file system sync on Android, but instead use WebDAV if it’s possible. If you are syncing the file system directory with a cloud service supported by the RoundSync app, then using RoundSync is the best way to go. See Could you please add the function of synchronization to FTP server - #5 by mrjo118