Good cpu choice for workstation (slightly confused at current options)

Hi, around 6 months ago or so I started to eyeball an upgrade path for my workstation.
I am currently on an I7-920 rig with 12gb of ram and a gtx 670 so yeah it has been a while.

Workload: Zbrush, Blender, 3ds Max, Premiere, After effects, Adobe CC and so on.
I was planning to go with dual xeon or something ridiculous like that but I have come to realise that it would be a better idea to get a "reasonable" high powered workstation and then have extra renderslave because having your main rendering machine be also your "other work" machine while you are rendering is not about the power resources you have but instead becomes a stability risk. That says to me that it would be a better idea to go with something relatively quick in most workflows and leave the numbercrunching to either it and walk away from the computer while its rendering (we would all benefit from a workout anyways right?). This will need to last me the next ~5 years but inbetween upgrades might be possible (newer video or whatever).

Also will want to go 4k for productivity reasons mostly.


6-8 Core:
(dual xeons maybe not but considering the odd state of available cpu's I wouldnt mind using a comparable Xeon as a desktop cpu but would like to avoid "unreasonably" expensive options).
Whats currently confusing is to understand if 5820 is still an option compared to 6800K and such? There are several very similar cpu lines out simultaneously which confuses the bejesus out of me- even some xeons look like they could fit the bill.

32-64gb of ram:
It is my understanding that the high-performance ram is mostly overkill as it changes very little in terms of rendering/real world use (not important to gain ~5fps or 5 seconds).

Because I want to start with a single gpu and drive 4k not sure if it would make sense to add in another one later on just for CUDA but I have not used cuda in my workflows too much yet so I do not know.

Other bits:
SSD's and probably "big air" type cooler, minimalistic but functional case and a 4k monitor (cant decide if 4k samsung tv, Wasabi mango or maybe even the philips or some other 40" monitor.

Gaming /screens:
I do game but not competitively, I do like shooters but again but mostly single player. Will not be playing competitively but would not like to encounter "input lag" that I can notice if I cant I don't care. Will watch movies etc. So considering 4k Samsa because they seem to have 4k tv's which can have very reasonable input lag @ 4:4:4 chroma ~38ms in PC mode and ~22ms in game mode. If those numbers are something I cannot sense then I would not care and get the tv.

However I assemble them prices seem to turn out similar.