I am level 38 100 in smithing and all my weapons and armor are legendary and I have The Lord stone for extra protection and magic resistance, and 100 in heavy armor and have dragonplate and am 693 in damage resistance. I play on master and already beat the main quest, but bandit marauders take out half my health with a single lightning bolt and ancient dragons instantly kill me with their fire breath and their instant kill animation always plays after it has bitten me once. I also have 100 in two handed, but my daedric warhammer doesn't seem that powerful at 111 damage. Enemies still seem able to really hurt me.
I don't have online so my game is unpatched btw.