Hoi
Well, whether the 2GB is enough definitely depends on your requirements: If you "only" use NAS file server functions, then the 2GB is enough. If you want to install and use applications such as groupware (keyword "Photostation") or Surveilance Station etc. pp. then it could be a bit tight.
As information from one Syno user to another: I use 3 models: an older DS409+ (RAM never removed, worked quite well without), a DS415play (RAM also not removed, would have made more sense over time, but:) and a RS3617xs - and I have now removed the RAM to 32GB because it simply makes sense on this part (Nextcloud, Apache, Containers, Plex ...)..) - My tip: Just use it "as is" and as soon as you notice: it's going down the drain with all the apps I use: then expand it.
You need the M2Cache if you want to access the same rather small data/files/especially blocks more quickly - probably more for corporate environments - here's something from Synology's KB about it:
https://kb.synology.com/de-de...Hope that helps.
