I am not sure why this did not work for you but to go on the safe side,
You can try to use the default format for the timestamp which is
yyyy-MM-ddTHH:mm:ss:fffffffK (complies with ISO 8601 standards). For example in your case:
convertFromUtc('2022-01-23T21:50:01','New Zealand Standard Time')
Or try to use
convertFromUtc(formatDateTime('2022-01-23 21:50:01', 'yyyy-MM-ddTHH:mm:ss.fffffffZ'),'New Zealand Standard Time')
You can help improve the document and get credit on doing so as well. The docs are manages on GitHub and anyone can send pull requests (suggestions for update). On the right upper side of the doc you have link to edit the document. All you need is a GitHub account.
The "magics" of commuters is exactly what lead to the uprising computers. Did you not see The Terminator?!?