4K editing machine

Here I am diving head first into this 5d RAW thing
Now, I don't shoot 4k now, and I'm sure I wont in the near future, but for the sake of being future proof, I'd like an editing machine that will work with 4k footage. What can I buy for under 2,000 dollars that will allow me to view native & edited 4k footage in say adobe premiere/Davinci Resolve without stutters?
Im a current mac user, but since this will only be a 'work' setup, it would be cheaper to go with a windows machine

Future proofing computers is a very difficult (near impossible) thing.

Having said that, if you want "top of the line" I suspect you might need to go down the dual socket route... and for high end video production I think that would be the norm, plus some good graphics cards.
HP makes some overpriced Workstations... Dell produces yet more overpriced stuff...
Fujitsu makes very nice reasonably priced computers and workstations.

You will possibly need input from someone who has dealt with 4K or even just 2K footage to get a idea what kind of specs you actually need.

My computer can handle 4K pretty decently, time-lapse footage that is, rendered through AE.

You will need lots of G/DDR5 RAM for rendering also too keep in mind.