This is exactly what happens when a game lets you power level way beyond any of the content, in the first area. The worst part is you didn't even really try, the game just has shit balance so you naturally level up to max if you fight everything you encounter. After that its just..whats the point?
Reminds me of playing kingdoms of Amalur: Reckoning. Fun game but if you do things properly you end up at max level waay before the end. I can't even bring myself to finish. I mean it feels pointless when you know "this is it" in a game like that. I mean i may as well go play tomb raider or something where the character has no leveling mechanic. Without room to grow it just becomes going through motions.
I even looked into modding it but its not that type of game. No mods to raise the max level unfortunately.