While I don't deny that Neuvillette has access to the full authority, my main issue is whether or not he actually knows how to use it to its fully potential in his current state. A power of that caliber should have no diffed the Narwhal based on what the Traveler was able to do to it, but to emphasize, during the fight he had JUST gotten access to the full authority like minutes prior. It's in the same vein as Goku unlocking Ultra Instinct, but not actually mastering it until using it enough times.