It seems like you currently have it coded that way.
The pos
variable of your statement is only a zero vector 3 when there is no input of the keys. When you press a key you create a vector 3 to move the player in a certain direction.
Maybe you can try the code below.
if (!pos.equals(new pc.Vec3(0, 0, 0))) {
this.entity.translate(pos);
const { x, y, z } = this.entity.getPosition();
this.app.fire("loadbalancing:sendPlayerPosition", { x, y, z });
}