Issue just started yesterday and most of the KR nodes have been unstable except for Azure(but Azure doesn’t work for Lost Ark for my end) , so just making sure if the other KR nodes issue is my end or yours, since there used to have announcement on the Dashboard whenever there’s problems
add:-
sometimes the VPN seem to affect other games even it wasn’t selected for those games (while not on FullVPN mode) issue doesn’t use to happen before few months ago?
Umm… At this moment I can’t see any issues on your RTT information from SG to KR. 
If you’re familiar with WinMTR, please try to test to the public IP of mudfish nodes which found at http://mudfish.net/server/status link.
Regarding to this question, please note that “LOST ARK” game item has CDN and Mudfish issue.
Most nodes are fine now , it was just a huge hiccup 2-3days back , GNJ nodes still unstable tho was 78-140RTT , now is ranging between 250-400+ ,other nodes had the same issue few days back but most have recovered except for GNJ , could possibly be ISP issue?
Might be yes or submarine cable issue in my opinion. 
Good to hear that most of them are recovered.