You are supposed to figure out the best items, you know this is a RPG
I don't know how to say it correctly, but if the goal is to beat the final boss, the best route you can take is through quests, by finishing them you can save money to buy the best equipment in the game, if the goal is to finish them in a specific way without losing your virginity or anything, do the other endings or scenes in the game to get more starting points and have an advantage.