Not sure on what to upgrade next =(

An average zhelm gives you 39.5 accuracy and 15 str. It's really hard for that to be over-hyped, being that it's the biggest boost one piece of equipment can pretty much ever give you, and that's before you even scroll it's 10 slots.

I meant before 80.
By then, all those benefits will be definitely useful. However, when I see most of these threads, it's always "get a zhelm, buy a zhelm"

It's always been that suggestion, despite the other more important issues.