I think (know) in terms of ultimate earning potential he is far better off coming through the NCAA system. I'll give a good example. Maia Ramsden is not as good an athlete as Cam Myers right now and probably doesn't even have more potential than Myers (no disrespect to Ramsden but you know, Myers is pretty epic), but she makes more money. She makes more money because she is US based and was a dominant NCAA athlete.
What Ruthe makes from his NIL right now I think is pretty good for a 16 year old in NZ. I think most importantly it keeps his options open. Let's say his rapid progress drops off slightly in the next 2-3 years which would be completely normal and wouldn't mean anything is wrong - it's just what can happen. Having the NCAA to go to is such a great option and you aren't locked into a deal that could easily be ended at the end of an Olympic cycle and could stop you from doing something in the future.
I think you'll see Sam Ruthe in the collegiate system, that's my gut feeling.