Red Star 4.0 (2017). Good luck finding it, I haven't.
I think that there was a rumor that it was FreeBSD based instead of Linux based but don't quote me on that.
However, they did takes a few screenshots. Red Star OS 4 is still MacOS-inspired but with a little more modern of a Mac look - think Mavericks (Red Star OS 3 inspiration) -> Yosemite (Red Star OS 4.0 inspiration). With a touch of Chrome OS and GNOME in there for good measure.
https://www.nkeconomy.com/news/articleView.html?idxno=3191
Might just be a game of finding someone who goes to NK for teaching or the like to pick up a copy while there for archiving