Just a heads up, all mods have basically zero impact on FPS. Meaning courts, stadiums, cyberfaces, globals, lighting mods, etc etc
The only mods that I have used that can impact FPS a tad are "reshade" ones that use an external plug in of sorts, and sweetfx type mods. All the mod screenshots you see though in the 2K20 screenshot section are mods that don't impact FPS, they are global and stadium mods. So I would take the "will mods hurt my FPS" question out of this.
As far as 4K with HDR graphics cards (ones that have those capabilities, and not just capability, but do it well), and processors that handle those cards, have you done any research at this point? And if anybody else wants to jump in and give him recommendation on that specifically, please do. I do not play in 4K.