Chaos/Lightning build cannot (be bothered to) get past act 2

I made a hybrid of chaos DoTs and lightning melee. Absoloutely ripped through mobs and bosses were challenging but after a few attempts no problem.
I rip through the Dreadnought and its great fun!
Then I hit the boss and next to no damage. I realise he is resistant to lightning, but Chaos DoTs alone should burn him down with patience - but they barely touch him.

I rerolled lightning to ice but I dont have the gear or the passives. Runnig around maps i've played numerous times doesn't seem reasonable because I kill everything else so easily - its just dull and long winded after a while.

Its possible I need to git gud...but I'm not going to because I love this character and this is a hard stop. I cant (be bothered) to get him below 80% - would take so long.

Was really into this one :(