I will probably upgrade by current system with a mid-range RTX card, and maybe a new i9 processor. A new monitor is needed as well, so I have some work to do before I am ready. I could probably run it fairly well on my GTX 1070, i7700, but I really want the best experience possible right from the start.
My goal is to be able to play at Very High detail at 1080p with steady 60fps. I don't know exactly what system is required to play at Very High or Ultra detail at 1440p with steady 144fps (which would be absolutely awesome), but it's probably too expensive for me at the moment.
When it comes to 4k I just don't care.