I think the disconnect you are having here is that you think CFML has multi-dimensional arrays: it doesn't. All it has is arrays that can, themselves, have element values that are also arrays (and so forth).
So array functions don't operate on multi-dimensional arrays because there's no such thing in CFML.
The arrayNew() function is a bit misleading because it claims it creates multidimensional arrays, but it doesn't really. For all intents and purposes arrayNew(3) does the same thing as arrayNew(1): creates an empty array.
If you have this array:
numbers = [
You cannot use arrayFInd() on the numbers array to find "tahi", but you could use arrayFind() on numbers. This is no help if you don't know which "sub array" the thing you're finding is in.
TBH, there's seldom requirement in business type code for multi-dimensional arrays, and where people do use them, they really ought to be using arrays of structs, or arrays of objects, or similar. What's your data structure here? I ask because one can use structFindValue() to find values in structs irrespective of the complexity of said struct.