Judgung by the current effort for just one mode, which should be around zero somewhere, I do not have high hopes.

thats a huge upgrade, try out to run this game on your PC in 3200x1800 and 60fpsish for 400 bucks, and the PS4 Pro will still look better because of its checkerboard rendering techniqs. Drops to 50fps isnt as a big of a deal on console as DF wants to make it up be because you arent playing in front of the TV.
The PS4 Pro is massivley stronger than the Xbox One or PS4

PS4 Pro: 5,760,000 Pixels
PS4/Xbox One: 2,073,600 Pixels

thats almost 3 times the pixels

Killing Floor uses the last generation Unreal 3 engine, albeit modified. So it's pretty light.
With that said Checkerboard 3200x1800 should be using 1600x900 frames which is then upscaled/downscaled via the scaler to fit your display.
1800P is actually a good resolution fit for Checkerboard all things considered as you maintain the 16:9 aspect ratio and it fits in with the capabilities of the mid-range graphics hardware.
As for framerate drops. No. They aren't okay. They should have went with high-equivalent PC settings rather than Ultra or locked the framerate to 30fps.

For $400 USD, I can upgrade my PC that is older than this generation of consoles and easily surpass this though and actually do real proper 4k.