HOW TO DEFEAT THIS GUYS😭
In addition to other suggestions, it's worth noting that that dungeon is a big reminder that 'you are an alchemist, have a lot of potions on hand'.
Having a bunch of sleeping mist and strong healing potions can help you recover and deal with some very tough foes.
Also, wearing good armour will help you here. Diablosite armour works well, as does Emerine armour if you can get Emerine from 'where you are presently standing'.