The guy from the linked TikToks does mention that he also hosed the inside of the trunk after returning from the beach, that might have been it.

That's always a risky thing to do, even on "conventional" cars (or maybe it's just Volkswagen Group cars that have a habit of electrical malfunctions every time there's water in unusual places involved).

With all that said, last time a car-wash fricked up some of my car's wirings it only meant that a back-light stopped functioning for a day or two (again, maybe this is just a Volkswagen Group thing), while in this case the whole car/truck got bricked. That's not ideal.