This model shows that even a small 2-disk desktop NAS can pleasantly surprise with storage capabilities: up to 4 NVME SSDs and up to 16 hard drives when using cards and expansion shelves. The ability to configure layer-by-layer storage and run applications in containers in a compartment with a 2.5-gigabit network makes it an excellent choice for a modern office with remote access and Wi-Fi 6.
The most difficult thing is not even to pick up packages to replace Synology services with free ones, but to support their work, promptly responding to glitches and updates. This is not an easy, but doable task that can be completed in a few weeks.
What can Synology be replaced with in the conditions of sanctions. Part 1: Choosing a stable platform.
You are very lucky if you used the NAS's of this company only for storing files: you will easily find a replacement for yourself. It's much worse if your business is actively tied to DSM services, including those related to virtualization, video surveillance, backups and fault tolerance.
Do you install new SAS-12 or SATA-600 hard drives into a self-assembled server or workstation, and they do not start and are not detected? The controller does not see the HDD, there is no sound of the spinning platters and the cracking of the heads? Even if the disk has worked in another server before, it does not start either in the disk cage or when cables are connected directly? Most likely, you bought the disk at seconadry market or from an unofficial seller, but do not rush to apply to the warranty or return the money, as the solution may be simple or cheap: it is possible that your HDD supports the Power Disable Feature technology, which prevents it from starting in the server. This is a fairly old problem, but there is not much information about it on the web, and the solution is simple and trivial.
A simple inexpensive NAS that has Plex, Owncloud, Nextcloud services, supports Docker, cloud management and its own backup system for Windows and Linux clients. It can work absolutely silently by turning off its fan.
A very unusual NAS, which the manufacturer himself considers to be Smart Edge switches. It has a built-in PoE switch for 16 ports, as well as 2.5-Gigabit Upstream interfaces and a software architecture with isolated network spaces for video surveillance.