Act 2 boss axe sweep and general difficulty

So I feel like I'm stuck at that boss for now. I did it with my first character (Frost sorc that's now unplayable, fu) and it felt fairly tough, but I did it in 2 or 3 tries

Now doing it with minions feels close to impossible. The damage just isn't there and that one axe sweep move that seems undodgable just chunks for 50% health every time and so eventually I just lose. Doesn't seem like there's much to do either. Grind levels doesn't do anything. Can't grind gemstone levels either. Hoping for a slightly better (basically perfect) scepter by randomly doing some zone also doesn't feel good.

No idea what the aim was here, but this is overtuned as fuck with no real way for the player to overcome it. Might work for some classes/builds but for others it's just a hard end to the playthrough