That's literally industry standard dummy.. If you open apps like discord or steam you will notice there will be 2 icons in your taskbar, one is the application, the other is the patcher, you just don't notice it because they have the same icon.
An executable CANNOT replace itself while it's running so a patcher must do the work, there are no exceptions in the world to this.
Metin was literally the only app in 2026 that required players to launch the autopatcher instead of directly opening the game and then it does all the work itself.
And yes opening the game once and then it updates itself and re-open itself when done is literally the best user experience you can have, that's why it became industry standard. I don't know how you can think having 2 launchers in your client folder, one to open the game and one to update it, could be a better user experience.
Lastly but not least, that's a free system, if you are one of those people that don't understand how modern workflow works and would rather keep living in 2004 just don't use it, why would you be mad about a free release