This is a fairly new, unstable, actively-developed Android app called Round-Sync. It is Rclone for Android with added triggers and schedules. I recommend an eye be kept on it it for possible recommendation once stable.
Though not exactly a privacy tool, it is a way to manage backups on Android without proprietary cloud storage apps.
So you could have your Cryptomator vault backed up to various cloud storage drives, all from the phone.