It seems IL2:BoS current textures are of the 2k standard, or 2048x2048 pixels. In short, a 4k texture is a texture map with dimensions of 4096 x 4096 pixels. A lot has been said already, but maybe I can add some insight into textures and normal maps*, as I have some background in hobbyist 3D-modelling, game programming, and texturing.
