When remotely accessing data, I strongly advise you to inform yourself in advance that this can be done securely. Because as soon as a NAS can be accessed from the Internet, there are also dangers, and the subject is unfortunately complex.

Therefore, my tip is to only set up something like this when everything possible is ready for it in terms of security. Virtual Private Network, firewall settings, port forwarding, everything has to fit and you really have to trust these solutions. If in doubt, it's better to do without and use the NAS only on your own LAN at home for the time being.

According to my own research, remote data retrieval is possible. Depending on the RAID, it is not possible to provide the individual disks with individual passwords, but individual folders can be encrypted or access can be provided with authorisations. :)