As for dynasty weapons like the Sword of Compulsion or the Staff of Dragonbone, I can recommend using them because they either give you Destroyers or dragons, which can be used as cannon fodder. And battles are completed with almost no losses.
You also need to choose the right skills for your hero... tactics, regeneration, pushing back the enemy, freezing...
Are you playing the Book version or the Steam version? I haven't played the Steam version, but the Book version works fine, without any bugs or anything.