The processor is $10 cheaper at Microcenter right now. Plus it usually goes on sale. Microcenter will also price match Newegg, Best Buy, and Amazon.
In fact, I would just pay attention to
https://www.reddit.com/r/buildapcsales/ and see what goes on sale. Right now the Ryzen 3 2200G APU is on sale for $70. Same as a 1600, but still. Lots of stuff can be had from that subreddit and Ive lost some money following it. LOL.
I know the jury is still out, but I gave my daughter a PC I built with an Inland Pro NVME 250GB drive that was $40 and its been on for a little over a month and having no issues. The 1TB model is around $100 if you want more. Id honestly just make the trip to MC and get your stuff there.
Instead of windows, and with wanting to do a plex server as well, why not look into Freenas or Unraid? Most of what you want to do can be run in a docker container while having data redundancy with a parity drive in unraid or a straight up raid configuration in freenas.
Ryzen loves faster memory for sure, but I doubt he is going to be gaming or doing anything mission critical. I would think 2666 ram would be fine for his application. Otherwise, yeah, Id go 3000 or above.
As stated, while doing this build, just set it up as a server vs a window machine. I know [MENTION=2933]Thirdgen89GTA[/MENTION] uses freenas, and I use unraid. I chose unraid over freenas just for the simple fact that I can add and swap drives that are different sizes as I need or as I see fit, while maintaining a parity drive for redundancy. I know there are multiple threads on the unraid reddit with people saying they left freenas or other free NAS software solutions for unraid for that fact and that the dockers vs jails and VM support was way more abundant. Either solution can work for you, or you can go windows if you want. Just throwing that out there that if you are building something from scratch, Id make it a server right out of the gate instead of setting up your thing now and then doing something else later.