How can I change proyectile damage when the proyectile is in the air?

Ok, so the title say the question, I want to make a canon weapon, whit varietes from wood to netherite, And ammo of that materials.

The canons Will use like this: You need to have the canon in your main hand, and the canon ball in the secondary hand, I have a idea of how make the Canon can use all ammo materials (Something whit tags and procedures) but i need to now how to change the damage of the bullet in the air, my plan Is make the bullet detect the player, detect what cannon have in hand and modify the damage, but how can I modify the damage? I think something whit NTB variables of i dont now

Somenone can help?

And sorry for my bad english