No hp or res can save u buff def across the board like effective health

So i have made a 15k energy shield build and 3k health i got shrine buff had 20k total health r well i get 1 shot i hit by a t15 boss, i well add even with chaos immune and max res and plus 50% armor still no matter the armor no matter the health no matter the res u get 2hit by t15 and even t4 maps,im 92lvl its impossible to lvl u cant stay alive even rn i got max res 10% armor 2.3k health,im doing 87k molten blast damage i can do t15s,i have desth rush and decent life on hit it not ganna help me cuz i get 2 hit,plz take away xp on death i cant lvl no matter who i join i cant stay alive i have a end game build i have tryed extreme tank or extreme damage damage is the way to go but i still die. Ty ggg plz fix