stuck on t12 maps

Hey guys. I'm a new player who got seriously stuck into 300 hours of POE2 endgame and came back to do the same with the first game. I've been loving it, and the different systems aren't TOO bad but obviously it's had 10+ more years of development so that's expected

The problem is, I've been levelling a Juggernaut and loving it (not as much as cyclone tho) and I've hit a wall and can't quite work out what the problem is I had some help crafting my gear with what currency I have, but two or more sets of eyes are better than one.

My issue is that I'm getting MELTED in t15 maps. I do look at modifiers like stun resistance or phys reflect when juicing, but my ability to be 1 shotted on such a tanky build seems wrong. Keep in mind im dodging mechanics as much as I can.

https://poe.ninja/pob/6f4ba