Why do I keep getting randomly 1 shot?

Character name: Berze_Lica
I have 10k armour, 5 endurance charges, 77/76/76 capped resistances w/o endurances, 20% less dmg taken from fortify, 10% less damage taken from nature's patience, another 19% less damage taken from permanent berserk, 11% less damage taken from enemies farther away from flesh and stone(I map in sand stance), 30% overleech from soul tether combined with pain reaver from ascendancy, 30% attack block and 7% spell block, 35 lgoh with 3.5-4 aps per storm with 4 bladestorms and another 8 bladestorms from the saviour, 1k hp regen with 6.2k hp and 1.2k es and with all this i get randomly 1 shot from delirium monsters, and it happens often.

The scenario that keeps happening is: I have a couple roots on me, berserk active, forify endurances etc up, i leap into a pack of mosnsters, i stand and hit them a couple seconds, enough to get max roots and have full defensive bonus from nature's patience, energy shield is almost full(~1k) hp full then, out of nowhere 0 hp 0 es, i died(it wasn't from chaos dmg because then i would've had some es left)

All the bosses are really easy, damage is good, normal juiced mapping(w/o delirium) is a walk in the park

I want to fix this problem as soon as possible so i can start enjoing the league again

Thanks in advance for the feedback

This is the league where you need to avoid damage entirely rather than try to tank it. Be it block, dodge, evade, or simply not being in position to get hit at all.

Delirium mobs are particularly brutal. The spiky ones randomly explode like porcupines on death and will shotgun you dead. The melee gorillas are fast and can leap slam from seemingly off screen. The casters have fast moving difficult to see projectiles that hurt. Any of these or a combination of all will rip you up very fast even with the best mitigation.

The best advice ive heard from the hardcore side of things is to max out avoidance, preferably more than one, and keep vigilant during delirium as the tried and true strat of killing them faster than they can move starts to falter as the mobs grow more tanky.

It's hard to identify the cause when you don't even know what killed you, is it physical damage or elemental or DoT, are you stun locked or frozen, mana issue, etc ? Those are common issues for a melee build.

Your gears are pretty good, no problem with that, but I do have a few suggestions:
_ Level up CWDT + Immortal call a bit (lv5 for example), throw in Increased Duration support gem to make better use of your 5 endurance charges. Higher leveled Immortal call provide more phys/ele damage reduction.

_ If you think you have enough DPS, replace your Vulnerability with Enfeeble (or Temp chain). Can be combined with the 4th link CWDT setup.

_ If you have already capped res, why use Wise Oak ? you have no elemental damage. Might wanna replace it with a defensive flask, Basalt/Quartz/Granite or Quicksilver to get out of the mobs quickly. For unique choice, look for Rumi to further boost your block/spell block chance or Taste of Hate.

_ None of your flasks have quality on them. Might wanna look for Life flasks with % recovery rate or instant recovery/ 100% recovery on lowlife (I dont remember the prefix/suffix).

_ Trust me, you don't really need that much life/mana leech, plus you already have some life gain on hit. There're plenty of sources for life/ mana leech like jewels or cluster jewel mods. You can anoint the Soul Raker notable in the Claw cluster, that node alone is enough to cover your mana and life leech issue, plus you have 50% recovery rate from life leech without having to take a "Savage" hit to trigger Pain Reaver. So you can use those free 2 points to get Flawless Savagery.

_ Your tree, going to duelist area has many more defensive/ ultility nodes like, weapon range / aoe, endurance charges, foritfy effect, block, etc, unless you really want the reserved mana reduction nodes in Templar.

_ Optional: Get a totem or golem, they can attract the mobs. I don't know your Pantheon but should take a look at them, they provide many defensive/ Quality of life buff.

All of those tips should enhance your survivability greatly, Im also a melee build with "free" 40% damage taken from Abyssus and only died to 1-shot by A8 Sirus.