I'll say that a quick test on my machine seems to hold at 60 fps no problem, with three layers of video over an SDI monitor output
i9-9900k @ 5 ghz, 128gb ram, RTX 2080ti
And when you think about it, 1800*2000=36M, which is just over what standard 8k is (33M), so as long as you build with 8k in mind, and are smart about flattening content when possible so as to not overload your ram and vram, you should be fine.