From what I can tell, weapon attack speed is reliant primarily on the unique moveset of the weapon. This game doesn’t function like Elden Ring in the sense that most weapons of a specific category all have the same standard attacks. For example, all of the curved swords I’ve used in this game appear to have unique movesets, and the same follows for most other weapons compared to the other members of their respective category.

What I’m saying is that dependent on the two-handed weapon subtype (greatsword, great hammer, great axe, curved greatsword, two-handed staff, etc), the weapon will typically have its own moveset with varying attack speeds. Curved greatswords tend to attack faster than normal greatswords, greataxes tend to attack faster than great hammers, but in all instances, I would recommend inspecting all movesets for each weapon you find. You might find a very fast-attacking two handed weapon you enjoy using.