is all "explicit" casting in my understanding, one way or the other, and the first ... as ... being on the lowest level.
I'd rather go for something like "do the casting close to the source, and in general use 'parse, don’t validate'[0] when getting input from the outer world".
The as also does not burden the reader with guessing about the absence of unexpected stuff happening in the functions. Don't pepper the code with mostly unused hidey-holes just to perhaps save some busywork later.
If you do add valuation, make it an honest asValidatedAccountId("123"), not an accountIdFromString("123") that may or may not do more than casting.
(PS, very much off topic: speaking of hidey-holes, are any of the AOP monstrosities still operational?)
I'd rather go for something like "do the casting close to the source, and in general use 'parse, don’t validate'[0] when getting input from the outer world".
[0]: https://lexi-lambda.github.io/blog/2019/11/05/parse-don-t-va...