I have a DS923+.
The first thing I did was install more RAM. Then everything I run is via Container Manager (their Docker version, which is a bit behind).
It is a great little machine. I use it for OneDrive and Google Drive backup. I use it for Office 365 and Google Workspace backups. And because it is always-on, I use it as the exit node for my Tailnet.
I was hoping for more of a discussion on the data integrity side of things. One of the biggest reasons I run ZFS is to help ward off bitrot. My understanding with most if not all COTS NAS devices is they lack any scrubbing or data integrity tracking, much less ECC.
I have a different Synology model (added extra RAM because it serves as an *arr server at the same time), and while I'm a big proponent of FOSS I must say that the 'peace of mind' section in this article really hits the mark. Hacking things together yourself is great, but when it comes to 20+ years of your digital data, I'd rather be safe. Also, encryption on and Synology QuickConnect (or whatever its Tailscale variant is called) off as a default.
These things are expensive... I ended up going with a DAS, a Terramaster D6-320. It was less than half the price (270€), suits my context (network-access isn't a must; the DAS is small enough to fit behind my TV), it doesn't "force" me to upgrade my network to 10gbps (expensive!) to get reasonable performance (it's USB 3.2 gen2 - 10gbps), and I can always make a DIY NAS out of it if one day I need to.
I currently use TrueNAS Core on a (very) old 8-bay Dell Poweredge system, which I have been trying to find a replacement for. Suitable server hardware seems surprisingly expensive. Is there anything like the Synology that is just a bare-bones system I can run my own OS on? Since TrueNAS abandoned BSD, I've been wanting to switch to a plain FreeBSD system.