#vehicle

Input.Pressed and Input.Down read a global input state, not a per-entity one. A component that reads them in its own OnUpdate samples that global state once per instance. With one entity on screen this is correct. With many non-networked instances of the same component, one keypress fires the action on every instance at once. Gating only on IsProxy does not help, because IsProxy answers whether the entity is replicated, not whether this instance should own the keypress. Gate the input read on genuine local ownership instead.

A collision rule that keys its direction on the struck object's own velocity is correct for the object that caused the hit and silently backwards for the object that got hit. A car rolling forward at 2 m/s and rammed from behind reads as moving forward, so it dents its nose instead of its rear. Derive the direction from the negated impulse delta-v, which points from the struck face inward for both bodies.

When a continuous-float render surface sits over a quantized-step collision mesh, every quantize boundary becomes an invisible vertical wall the player hits but cannot see.