>>719923652
>I ended up a little underleveled at the E4

Oh boo hoo the last enemies in the game aren't an automatic win.

Let me tell you how the grinding was done when we were men while being kids: we bashed our heads against the Elite 4 and every time we got a little bit further it was an exciting new thing. This is likely something you are physically unable to understand so don't be too hard on yourself.