WTF is up with all the damage?

I shouldn't feel like my character's made of paper when I'm in unjuiced low to mid tier maps just trying to fill out my atlas while playing an RF build. Granted, I haven't thrown a bunch of divines I don't have yet into the character, the defenses are nowhere near where they could be, it's still mostly cheap rares and uniques I either found or bought for a handful of chaos, but 1.8k life regen, 82% fire res, 79% lightning and cold res, 9% chaos res, 5.4k life, 3k armor (5.4k against proj due to titucius' span), 39% attack block (64% against proj attacks also due to TS), a cloak of flame shifting 40% of my phys taken to fire, -30% damage from crits, and a xophgraft with heart of flame, should not feel basically the same as walking around with a completely naked character. but that's how it's been feeling all through yellow maps and I don't understand why.

I just did my first t11 of the league, an arcade, and the fire ribbon boss, which definitely should not have posed a major threat, was the most threatening thing in the map somehow; the fire rain move it does was somehow nearly two-shotting me, which it should absolutely not be doing. And to be clear there were no special damage mods on that map that could've explained that, the only damage multiplier mod on the map was the one that gives increased attack/cast speed to mobs, which shouldn't have made any difference at all to the magnitude of single hits of fire damage.

After getting through that t11, I got the black star invite and so I did the quest version of the black star. I have never before experienced actually spending all six portals on that fucking fight, let alone not beating it. WTF happened to the damage of that boss? I know I'm supposed to be in the hot zone for the cold skills and the cold zone for the hot skills, it's not only obvious but I've done it plenty of times before, usually deathless, and many of those times with a league start RF character little different from the one I'm now playing, but for some reason now, even when standing on the hot side, and avoiding all the big cold meteors, the small ones each do about half my fucking hp in damage. How? Was there some hidden other damage involved? That actually seems plausible given that she was doing seemingly half a dozen different moves every second for some reason (which I can only hope was a bug and not how that fight is supposed to be now). Or did you just decide to massively overtune the damage of the small meteors? Or perhaps the hot/cold zone mechanic was just broken? It makes no sense.

I'm not even sure if this post really belongs in feedback or if it should go in bug reports because it feels like something is very off this league, as if my resists maybe have some extra hidden -50% penalty or something that only applies to hits. I just don't get it.

Get more chaos res. The times where you could run around with almost zero chaos res, not to mention negative res are long gone. Your character is essentially naked everytime you get hit by chaos damage and it's rather common these days. After that, get more armor. 3k armor + cloak isn't much for a character that needs to get up close. I suspect even in yellow maps most map bosses can oneshot you with that, not to mention a bunch of mobs hitting you all at once.

Frankly, your gear is subpar even for yellow maps. Your helmet has like one useful stat and thats the life. At least dual res and life should be on every non unique gear piece. Doesn't have to be T1 mods, T3-4 is more than enough. Doesn't take divines to get that kind of stuff, picking up proper bases and or using harvest rerolls can get you stuff that's far superior to what you have now without spending a single chaos.

By the time you reach red maps you are expected to have your shit together, it's no longer the campaign/white maps.