Maybe not the size of Australia, but compare it to this map I generated (Winkel-Tripel projection) [1] where Korea is correctly sized, and you can see it's easily 2-3 times as big as it should be (in terms of scale).
[1] http://worldmapgenerator.com/maps/20200926110400_map_5f6f040...
Not really
> tiny sliver for the Japanese islands
As in any map
> places Korea at the absolute center
TBH, that sounds more practical.