Having this same issue. Unable to update launcher, uninstalled and reinstalled everything fresh. Redownloaded completely new game and launcher, got to a point where I could no longer update anything.
Circumvent the Launcher and login to the game via the .exe, it will force you to update, then say the update couldn't be applied. After that, restart the launcher, it will apply the update to the launcher, and you're in.
Good luck!