I’ve been using FolderSync. It let’s you sync to/from a remote server through a bunch of different protocols like SMB, SFTP, and WebDAV. You can schedule it to run automatically.

I haven’t tried it myself, but I think there is a way you can get Tasker to run scripts in Termux. You could set up your own rsync scripts that way.

Well, for one, it’s network attached storage. If it’s not present in the network for one reason or another, guess what, your OS doesn’t boot… or it errors during boot, depending on how the kernel was compiled and what switches your bootloader sends to the kernel during boot.

Just use nofail in the fstab.

Second, this is an easy way for malware to spread, especially if it’s set to run after user logon.

If your fileshare is accessible to you, it is also accessible to malware running as your user. Mounting the share via a filemanager doesn’t change this.