Greatswords added by this mod have a cooldown between swings of 10 seconds, whereas the Cleaver added by Tinkers Construct has a cooldown of slightly more than 1 second.

As far as I can tell, this is because the Greatsword has a base attack speed of 0.4, but for some reason 0.3 attack speed is subtracted for it, giving it an actual attack speed of 0.1 and resulting in a 10 second cooldown.

I can't imagine this is intended behavior, since the slowest weapon in Tinkers Construct (the Broad Axe) has an attack speed of 0.57.

In my opinion, the Greatsword should have an attack speed somewhere around the Cleaver (0.95), but slightly higher since they occupy a similar role but the Cleaver does more damage.

what mc version are you on?

I wasn't aware of that issue with the greatsword when I did testing myself

what mc version are you on?

Sorry about that, I meant to put all that information in the original answer.

I tested this on 1.19.2 Minecraft, with the latest release of Tinkers Reforged for 1.19.2 (not at home so I can't tell you the specific mod version, sorry)