Act 2 Boss

What is going on with this guy, his AOE is way too much and his tracking wands are pretty messed up too. I'm happy with a challenge, I'm almost 40 on a Mercenary wnf it's a little too ridiculous. Not my first RPG or game in general but some of this should probably tone down, it doesn't make sense on a midrange class to fight against it

Edit : the sandstorm stuff when you have enemies swarming you is so toxic because you can't move and you can't kill them. I loved this game til this encounter but I can't see playing it any further if I'm almost level 40 and confused how my character works