What part should I upgrade?

[WOWBOX40]

The 1070 is ok for a 5man. Its a bit similar to the 980ti.
Keep that and upgrade to the best you can afford later on, with a system like this. It will play a 5man very nicely.

https://pcpartpicker.com/list/BrKXq4


The motherboard can have 64gb ram. So if you want to 10box later, add another set of 32gb. Or buy the entire 64gb kit if you can afford it now.

I wouldnt buy a 6 core etc without hyperthreading. Rather save a little bit longer and buy a i7 or i9 ideally.