Well, I can only use medieval sources I'm familiar with as context. But, there, ship maps are more for showing the rough way to follow tides to reach places. Things look warped particularly to the modern eye.
That said, most of those either don't have a compass at all, or if they do what is supposed to be north is roughly north of the central point of the map. It just might be strangely too far west or east because the map maker emphasizes different sections of the path through the water.
So, going by that. Freljord is West, it just is probably not as directly west as it looks.
Also, the tech in Runeterra is far and away beyond anything in the medieval world, so, there maps should probably be a bit more accurate.