Well, your coastlines are rather off. You are using the Plate Carree projection (Normal Tangent Equidistant Cylindrical) to judge by the graticule (Which is a bit misaligned You shouldn't have any map north of 90° N for instance). That projection produces significant distortion toward the poles. If you draw on the map without that distortion, it means you've drawn the land with the opposite distortion to compensate.
So, in your case, the projection stretches things out east to west as you near the poles. As the land doesn't look stretched that way, it means the actual shape of the land is all pinched in toward the poles so that the stretching balances it out.
This is one reason real world maps aren't generally done in this projection, as the distortion it produces is particularly unpleasant (ALL projections will produce a similar amount of distortion, but they vary in how it distorts and where it distorts.
It's also odd that you have that land mass so perfectly centred on the pole. The huge peninsula sticking out off it also looks extremely odd and doesn't make any sense to my (admittedly limited) understanding of tectonics. The mountains look largely OK to me, except that peninsula again.
If Northania and Southaria are meant to be rifting apart, you might want to make the coastlines fit each other a bit better. They don't need to be perfect as it's the edge of the continent as a whole, not the coastline that's important but you places where you have matching promontories. Mountains along the rift zone are likely to be old and weathered like the Appalachians along the eastern US. You might have similar mountains in the south of Northania, or if there is a significant continental sea making up for the mismatched coastlines, maybe a chain of islands. If this is what you are up to, think of the two fitting together with mountains along either side of the seam, then moving appart. The new coastline would drop down a bit as this happens and will flood to form shallow continentals seas (The continental shelf). At least that's my understanding.