You can make a very educated guess. MW couldn't hold 4k/60FPS with no ray-tracing on a 2080Ti. It's all in the math. The bandwidth is just not there. When you guys want to ballpark what you think your next-gen console will do, it's very easy to compare it to the 2080Ti (which has more bandwidth and is faster at rasterizing and ray-tracing). If you know a 2080Ti can't do something, then you can rightfully assume that the next-gen consoles can't either.
I don't think Raven's fork of the engine will be as heavy, and any 120 mode would no doubt be on much lower settings than you probably would run on a 2080Ti to get 60 fps