An update: A guildmate on my Discord guild server helped me and we managed to solve it quickly.
They said it was a problem with CSS not loading, so they instructed me to manually delete the Nexon Launcher Folder from my computer after uninstalling the Nexon Launcher program, and only reinstalling the launcher AFTER I've done that.
So now after reinstalling the Nexon Launcher a second time its UI is back to looking proper again.
This is a grave game breaking bug that has been occurring to players since 2016 from what I can tell searching the internet about this issue.
Can this matter please be forwarded to the right people so that this bug can be fixed as soon as possible?
It's not reasonable that players will be getting banned for playing a key content in the game.