I would guess you have way over prepared for your battle with Bonemass. And with all that over prep you can get into a rut (well for some).

All you need is a banded shield, an iron mace and some poison resist potions to beat it down. As for armor -Troll is more than adequate.

Most boss fights really only require a few 'at tier' gear pieces to win, but many players are afraid of skill loss and don't want to push the envelope so to speak so they grind and grind in preparation and risk becoming bored.

Not that over preparation is bad if you like to do it (or are a completionist) it is just not necessary.

And in general survival type games are about getting better gear so you can go out and get even better gear to allow you to survive longer in more hostile places that might have even better gear. It is the loop.

@SiEgE I take it you don't use polearms, 2H hammers or Battleaxes? Stamina, at least for me, is the key in using these. With their AoE you can keep mobs away so you 'dont get hit' and don't need the extra health, but you do need the stamina as their use drains it quite quickly. So 2 Stamina 1 Health is my general combo for combat.