Why would you think a new rig is warranted just because of a GPU upgrade ? You only said PSU would be hard pressed but 850w should do it but to build a new rig ?? Now running triple monitors &, or VR would increase demand considerably as you know & that would justify more power. This can be be a tough hobby, not for the meek & I learned that I had to make sacrifices to buy the hardware if I ever wanted good performance. The thing is it’s never enough so it seems. I started with a I3 10100 & GTX 1070 on High End settings & it was often awful so I was able to get an RTX 3070 OC when they were still at about $800 only to find the 10100 was badly bottlenecked. I got an I5 10600K (at stock so far) and though performance is such that I can’t complain without realizing that many would have no sympathy yet I still crave that 3080 with a 10900K. I fear that this hobby is chasing scenery dragons and performance dragons with a finger on the pulse of my bank account.