As someone who's played both mage and fighter singleplayer, mage might as well be hard mode, and that's what i started with lmao. I recommend using the bell if you don't already, because it does additional damage and its way easier to hit targets with. My strategy with rooms is to keep backing up while you attack, and paying CLOSE attention to the monster animations, because they'll broadcast when they're about to hit you. Also, make sure you put at least some skill points toward dexterity, because you'll be able to hit from further away. Some of the dungeon waves are just straight up unfair, but still doable if you really pay attention