I’m not sure what if the correct shape of the S/N Korea is. (And possibly it could be different as their nationality/political belongs :P)
But if you are using Telegram, they has very active channel there.
Maybe it is better to ask this topic at the channel.
I do not use Telegram, if you do, then can you help me ask Korean map editors to review the “Northern Limit Line” (NLL) part of the border which doesn’t seems quite correct?
See also https://forum.openstreetmap.org/viewtopic.php?id=64911