Help with build.. hitting a wall at T15 Level 87 BloodMage

Heya... noobish issue here (played PoE1, but never late game)



So i'm following this crit/hexblast build

https://mobalytics.gg/poe-2/profile/5d1b06da-ed4d-4831-84c4-fb942a0203a2/builds/c1d540cd-886a-4c2b-83bd-4d8eeeceb54d

It did very well for me until i got to T15 and try Breaches, Expeditions, Delirium, and Rituals ... basically i get swarmed/surrounded so fast and I can't seem to kill them fast enough, or roll enough to survive them.

I don't have ALL the exact same gear, but pretty close. I tried that unique helmet (atziri's disdain) and one with better life/shield/resist, but didn't find much success with either.

I've tried bone cage as a CC and that helped but wasn't great, the person who posted the above build recently added those Ice skills, which i've been trying and I feel the bone cage was better, but neither are the "solution".

Right now I have approx 1800 life and 3500 ES before the overcharging from blood mage and grim feast

I can deal with bosses and mapping quite easily

I moved TO this build after using a DD/Bonestorm crit / physical build for the same reason, i felt like I was getting swarmed, especially in Delirium where I had no corpses to detonate.

I would appreciate any suggestions on how i can modify my build to survive these swarmy moments