The degree of squiggle is really the least concern I have. The consistency of it is more of an issue. It's just too regular. That could be explained as a stylistic choice by a cartographer who lacked precise geometry for the coastline, that has been done with real historical maps, but it doesn't make sense for the "real" geometry of the coast.
The biggest issue though is the arrangement of the world map and projections. If you want a realistic map, this is something you should really get figured out before you draw anything. In your case, as your world map is rectangular, I'll assume it's meant to be in some sort of Cylindrical projection, and presumably a Normal one (the equator is a striaght horizontal line on the map).
The "parallels" of a graticule are circles around the poles. The closer to the pole you get, the smaller the circle. Of them, only the equator is a "great circle" (The equivalent of a straight line in spherical geometry). On a normal cylindrical map, all the parallels are lines that run the width of the map. You can pick a particular pair of parallels to be "true" (the standard parallels) but any parallel outside them (close to the poles) will be stretched out and anything between them (closer to the equator) will be squashed.
The poles are likewise shown as lines the width of the map, but in real life they are single points without length. So the distortion is effectively infinite at the poles. A coastline enclosing a pole should span across the map and not touch the top/bottom. If the coastline runs exactly through the pole, it would appear as coming straight out from the top/bottom at precisely opposite meridians.
Assuming your original map was normal equidistant cylindrical and covered the entire globe, here it is in the same projection with the equator as the standard parallel and Earth's coastline superimposed. Note how Antarctica's coastline wraps around without touching the south pole. Also note how the shapes of the Earth coastlines are 'stretched' or 'smeared' out east-west the closer you get to the poles, any map in this projection should show that same stretching.
To get an idea of what the poles actually look like, here they are in stereographic projections.
There also also projections that can ensure everything is the correct size (at the expense of distorting shapes). This is an area preserving projection called Mollweide.
Here's a stereographic projection centred on the area you are focused on. Stereographic is a "shape preserving" projection which gets angles right, but distorts area more. As it's confined to an area near the centre of the projection, the amount of distortion is fairly small and greatest in the corners.
Finally, this is what your planet looks like from space (Orbital radius 6.6 times the radius of the planet, which would be a synchronous orbit for Earth)
Of course, all of those depend on assuming the original map was in that particular projection, but it's going to come out a bit wonky looking no matter what you assume there unless you work whatever the correct distortion for that projection is into it.