That’s why we have stuff like this in the New Player Help forum…
Just as an example, here’s a build guide for the Seeker of the Light set…
https://maxroll.gg/guides/sotl-blessed-hammer-crusader-guide
The suggested weapon (for non-seasonal heroes) is Johanna’s Argument which gives this effect…
Increase the attack speed and damage of Blessed Hammer by 100%.
100% damage bonus is a 2 times damage multiplier.
Attacking twice as fast is a 2 times damage multiplier.
As it’s a one-handed flail, you don’t need to use Heavenly Strength and you can swap to Fervor instead which gives you a 15% attack speed buff, which is a 1.15 times damage multiplier.
So, you have a 4012 damage Scourge, without these multipliers. If you get a Johanna’s with 2000 damage, that sounds like it’d do less damage, right? However, we have to factor in the (2 * 2 * 1.15) times damage multiplier, i.e. 4.6 times damage multiplier, so 4.6 * 2000 = 9200. So, it’s not a comparison between 4000 and 2000, it’s 4000 versus 9200. Swapping to the right one-handed flail gets you 2.3 times more damage.
No, it gives 38,000 Thorns, not damage. Unless you’re playing a Thorns-based build (such as the Invoker set) this will not markedly increase your damage. As I’ve previously said, you want an Emerald in your weapon, as this provides Critical Hit Damage. All build guides will tell you which gem types to put into your helm, chest / legs, weapon and legendary gems for your jewellery.
If you want an example of a Seeker…