Need help levelling up

I no joke have 42 hours in this kingdom hearts one proud mode Save, it’s my first time ever playing the game, and I just decided to brute force it for the first time, I’m fighting ansem 1 and 2, and I simply have hit a wall in this game, I’m too low level and I don’t know how to level up and every time I try to fight stuff to level up at seems like I’m too low level. I’m level 50 I just wanna be able to beat the game. Any tips on what to do.