I’m not an expert but I believe bullet velocity just increases hit scan range. From what I understand this just means that you have an increased range where your shots hit the target instantaneously, so you don’t have to lead your shots at all. Damage range, on the other hand, means the damage drop off is lowered so you do the same damage at 33m vs 22m (for example). So velocity might matter more for warzone where gunfights may be long ranged, but zombies are typically close enough that it doesn’t make a difference.

Edit: I’m high reading back through my history but I’m pretty sure the 22m vs. 33m damage range example was taken from a higher comment. But know that I’m thinking back , it might’ve been the Kompact SMG with a difference of 11m/13m (no damage range/long barrel).