I realize this thread is 2 years old but I found this thread looking up how to do this for myself since I hated having my Pokemon disobey me because I played the game lmao.... super anti-fun so I'm gonna leave the REAL solution below (all you need is the game and PC's default notepad)
Go to the game directory -> Scripts -> Reborn -> SystemConstants.rb. Open with notepad and the level caps for each badge are displayed on top, simply edit the numbers to whatever you like best. That's it, nothing too complicated, happy gaming!