This app was mentioned in 1 comment, with an average of 3.00 upvotes
The KT one is called olleh navi, and the SK one is TMap. They are both preloaded and not available on the play store, only in carrier-restricted stores.
Nevermind, I'm dumb:
https://play.google.com/store/apps/details?id=kt.navi&hl=en
https://play.google.com/store/apps/details?id=com.skt.skaf.l001mtm092&hl=ko