Pretty decent, the RTX 3060 average FPS at 1440P ultra settings is around 80-85 FPS. Which should be considerably better if you turn the settings down a little.
For a CPU resolution doesn’t matter. So it’s performance would be the same at any resolution. Few game settings affect CPU output. As it’s work is done before the GPU renders the frame.
Looks like a great screen. The user reviews are spot on. You’ll just want to adjust the settings when you get it. As reviews say the picture settings from the factory aren’t optimal. Which I don’t see as an issue. I always adjust my new screens.