You have to account for different types of map projections (like Mercator, Miller, equirectangular, etc.). It seems your map is equirectangular. All 2D map projections distort some region of the world, usually at the poles. So that is why you see a higher percentage of land mass at the North Pole. This is not due to there being more land mass in Russia/North America as represented in your visualization per se, but because the pixels represent a distorted map.
If you still want to do a pixelated method, it might be proper to acquire a 3D model map and use the pixelated coordinates of the earth’s surface in that manner.
Hope that helps!