From a quick look, Synology seems to be a proprietary [EDIT: not SaaS, just software]? I'll stick with Nextcloud, with which I am ethically aligned, thanks. [EDIT: point still applies. I'd prefer to use software that shares my values.]
Agreed, with one modification: anyone ok with using Windows or macOS should be ok with using Synology from an ethical perspective. Someone looking to transition away from proprietary OSes, or someone who is forced to use them for work but otherwise does not choose to use them, likely would prefer to avoid adding a new proprietary dependency to their life.
For myself, I am down to:
- Proprietary blobs used to interface with hardware (e.g. shipped with Fedora, used at boot time). I do not currently have a plan to address these.
- Proprietary applications/services that I am unable to uninstall from my locked-down Android phone (e.g. Google Play Services). Planned to buy a Librem 5 as my next phone, if I deem it functional enough when my current phone breaks.
- Proprietary chat applications for communicating with others (read: as a compromise to not withdraw from society): snapchat, discord, slack, zoom. No concrete plan to stop using these, but ongoing effort to convince others to use FLO tools instead (Signal, matrix/element, jitsi meet) and to compartmentalize and isolate them from the rest of my computing.
- Android studio. Rarely used. Won't need after I switch phones.
- Turbotax and associated Windows install, on separate hardware. Used once yearly. Planned to learn enough tax law to file by hand, or hire an accountant to do my taxes.
- Many games. I consider this acceptable given few FLO alternatives of vaguely comparable quality. In the past I have run a separate Linux install for gaming, but found that less than ideal. Planned to use a separate user account instead, or maybe a chroot or jail.
- Windows install, on a separate drive. Rarely used (maybe one week per year, usually for a game that doesn't work in wine). Planned to dump eventually -- at this point there are enough games that run natively on Linux or work in wine that I will never run out of quality games to play (especially as I have less and less time for this hobby).
FreeNAS - https://www.freenas.org/
Unraid - https://unraid.net/
OpenMediaVault - https://www.openmediavault.org/
You also have: https://xpenology.org/