My brother is building two systems for him and his wife. He tends to be the type that goes WAY over the top, and then uses that system for like 7 years until it's performance is lower than that of a middling current system. I'm trying to convince him to go a bit cheaper for once, save some money, and just upgrade the GPU in a few years. He indicated his budget is ~3k for each system, which I also feel is kind of a waste. He just does general gaming. No real streaming, nothing competitive. He does game development, but mostly 2d/unity stuff. No rendering as far as I'm aware, though he did mention he may want to look into VR dev at some point in this iteration.
I figure the best place to start would likely be something along the lines of a Ryzen 3800 or 5800 when they come out, 3070, 16-32gb of ram (Not sure if he does emu work with stuff). His only notable criteria is that he needs a lot of USB-C and USB3 ports on the case, as he swaps out a lot of external drives from developers. I guess he has 2-3 8-port USB3 hubs connected.