Spell damage does scale with the level but that doesnt matter much in that sense, because at those specific sections of the game you meet enemies of lower levels.

An actual RPG game is not supposed to be an action game where you have everything at your disposal completely freely and then its only up to you which combinations to use.

Different RPGs take a different approach to the balance of this, some make all of it inanely easy, some are more restrictive, some a lot.
I am not saying OS should be one of those that is very restrictive in this sense, which it is not - at all. But i dont see what kind of sense would it make to suddenly turn it into another mass market abomination by just allowing everything, every time, for everyone in any possible way.

Or into a class based game with those kinds of specific restrictions. Because simply - it was never meant to be such a game.