2+16, and yes. It would not make sense to install memory you can’t use.
But you still want better performance, right? Used ram is cheap on eBay.
They had certain disks on the compatibility list years after they themselves confirmed that those disks cause hungs and system reboots. They want to play big boys game but they can’t keep up.
This is in the same vein — that cheap plastic toy with soldered ram, lack of ESD shielding, and an external PSU from the lowest bidder that Synology markets as replacement for every cloud service to unsuspecting consumers is not even near the category of those dell, hp, and supermicro servers that makes expecting users to buy vendor disks somewhat reasonable. They do it because it’s a money grab. Synology is good at marketing, but their entry level line is aimed at consumers, who buys solely based on price; expect those consumers to then not to shuck easystores, let alone buy vendor disks is disingenuous.