FreeNAS Build Atom or Ryzen?

I intend on building a freenas system that will have 20 TB of raw storage now but might expand in the future to 30 TB.

It will not have heavy load, not more than 4 users at once. Usually 2 users. I plan on installing plex to transcode and stream 4K. There's only 1 4K TV so not more than a single 4K stream at once.

I'm looking at supermicro's Atom motherboards but they're DDR3 and I fear that it would be difficult to find ram when I upgrade the capacity in the future. The other option is one of the low-end ryzen.

Has freebsd 11 fixed the problems with ryzen? Should I stay safe and go with Intel? If so, should I get Atom?

Ryzen seems pretty overkill for a NAS particularly if its low workload.
There is still plenty of places that sell old DDR2 stock so getting DDR3 shouldn't be too much of an issue and is probably far cheaper per gig than DDR4 is right now.
So unless a Ryzen setup is cheaper somehow I would recommend the Atom. Unless you are willing to wait for the quad core Ryzen or APUs.

Wouldnt wory about DDR3 as there will be tons of stuff being removed from years as they go EOL. I started with a 4130t and moved on to a Xeon e3 1275L when I wanted more power. You cant really go wrong with any of the choices. I would be concerned about the Atoms as they had a huge issue recently and not sure how easy it is to see what ones have been fixed / updated.

I wouldn't mind it being overkill if the price is good. If Ryzen 5 1400 works well with freenas 11 I will get it.