Are you using 4K textures in the sim ?
KLAS has been designed to run in 4K, not to increase resolution, but to increase performances, since using less 4K textures is more efficient than using many 1K/2K textures, at the same overall resolution.
Which means, if you are not using 4K textures in the sim graphic options, you are actually *reducing* the original resolution of the scenery ground textures.