When running the game on 4K screen cursor is either boxed in top left 1/4 of the screen and transposing to rest of the screen (in Fullscreen and Windowed mode) or displayed on 1/4 of the screen in Borderless Windowed.
This makes this game unplayable for me.
Examples below:

Fullscreen as you can see cursor is in top left while selecting Options menu section.

Borderless Windowed this shows just over 50% of the screen area. And again cursor is in 2 places.

I've managed to fix this after modifying .ini file.
UserName\AppData\Local\BattlefleetGothic2\Saved\Config\WindowsNoEditor\GameUserSettings.ini
And those are my settings

[/Script/Engine.GameUserSettings]
bUseVSync=False
ResolutionSizeX=3840
ResolutionSizeY=2160
LastUserConfirmedResolutionSizeX=3840
LastUserConfirmedResolutionSizeY=2160
WindowPosX=-1
WindowPosY=-1
FullscreenMode=1
LastConfirmedFullscreenMode=0
PreferredFullscreenMode=1
version=5
AudioQualityLevel=0
FrameRateLimit=0.000000
DesiredScreenWidth=3840
bUseDesiredScreenHeight=False
DesiredScreenHeight=2160
LastRecommendedScreenWidth=-1.000000
LastRecommendedScreenHeight=-1.000000
LastCPUBenchmarkResult=-1.000000
LastGPUBenchmarkResult=-1.000000
LastGPUBenchmarkMultiplier=1.000000
bUseHDRDisplayOutput=False
HDRDisplayOutputNits=1000

It is a shame we as customers and end users have to fix any resolution issues ourselves. A spokesperson for Tindalos on these very forums said that they do not intend to support certain resolutions so it is up to us to make things as good for ourselves as we can.

Thank you for posting your solution and I hope others with the same issue you have had will benefit from it in the future.

I am hoping that at least after release Tindalos can actually address this issue to support all of the resolution issues players are having as their current supported resolutions are extremely limited and stating that they do not intend to support them makes them look bad as a competent developer.