Power for hammer ?
It’s not about better. GS just has higher damage capability at a loss of the hammer’s control options. Pretty intentional for you not to have maximum control and maximum damage all rolled into one weapon.
Anyway, no matter what stats or how much of them you stack, other weapons will do more than the hammer, so I dunno that you’ll ever be satisfied with hammer damage.
Have you considered experimenting with the one-handed weapons as a second set? For example, sword/mace? You’ll still have a knockdown and cripple, and you can build up bleeding stacks and hit mace 4 for vuln before switching back to hammer, and that might help your damage a bit. The shout “On my mark!” might be worth trying too if you’re okay with losing some utility to boost your damage.
Priorities, what to do?
Spend hours with dye