PoE Claws of the Magpie, Cold, Duration builds

I started the league off with Aer0 cobra lash build and I'm barely in to maps but it is feeling just really awful. Mapping is just really painful. Cannot even attempt Affliction stuff because especially my single-target is abysmal. I know I'm missing uber lab and only have 4 link and shit gear etc. but I've played enough of this game I know something is seriously wrong and getting a few small upgrades is not gonna cut it. I am literally killing some regular rares for a minute or something if they are any tankier. Also if they do a

Actually played this as Lightning Arrow for the majority of the league. I saw another post on this subreddit using Heatshiver + Immortal Flesh and thought to myself wait, that's like 10x better than Voll's + random Stygian. Went from something like 100m LA + Artillery Ballista DPS to I think 140m, due to heatshiver. Interested in taking the build further, if anyone would like to take a look at my POB and point out any mistakes/gearing upgrades I can make. Kind of unsure how much the 50% inc effect of ailments mastery is helping me, for example.