if you have fully decided to go with p2000, I would simply pop it in your existing system and make a test plex server with your existing components without buying anything else yet.
then you should be able to determine how many streams that current system can handle, and that will tell you if you can do with more or less system power.
don’t forget also, that for 4k DECODING you need windows currently.
p2k on linux isn’t going to help decoding 4k until they finish updating the decoder.
also keep in mind, if you are direct playing, you don’t need a huge expensive server at all.
