Why is my iOS 18.1 hearing test unable to classify results?

I don't think it's actually external noise but our own heartbeats. I used the plugs I normally use, which are a little tight for sports use, and I can hear my heart. I pulled them out a bit to be a tad loose, and the test eventually worked. And they do seem to work as hearing aids. Don't clear your throat or scratch your face. There may also be timing issues; when I got it to work, I tapped the screen just after the 3 pings, not during them, but that could be coincidence.

The software is unnecessarily difficult and I think the message is misleading. So it took me an hour to work it out, but that was faster than seeing an audiologist.

If you got a hearing test, the audiologist may be able to give you the audiograph file to load.

YMMV