Hacker flexibility or consumer take-it-or-leave-it, pick one.
Debian offers flexibility and control, at the cost of time and effort. PhotoSync mobile apps will reliably sync mobile devices with NAS over standard protocols, including SSH/SFTP. A few mobile apps do work with self-hosted WebDAV and CalDAV. XPenology attempts to support Synology apps on standard Linux, without excluding standard Debian packages.
Debian offers flexibility and control, at the cost of time and effort. PhotoSync mobile apps will reliably sync mobile devices with NAS over standard protocols, including SSH/SFTP. A few mobile apps do work with self-hosted WebDAV and CalDAV. XPenology attempts to support Synology apps on standard Linux, without excluding standard Debian packages.