I tested right now and it's 5:
Settings -> Accessibility -> Audio/Visual -> Background Sounds -> on/off/sounds/etc.
It may be the number of items that are part of why people consider these settings "hidden". The "Accessiblity" menu is now 23 items long, and the main Settings menu is 53 Apple items plus over 100 application items.
Well yes, when there are thousands of possible configurations to accomodate the vast majority of potential users, and to keep confusion to a minimum by assigning a unique place in the UI to every possible option, it has to be spread out a lot.
Even the most buried possible setting in iOS is 9 clicks or less, and for the bigger features usually a lot less as you've demonstrated, hence it's not correct to call it 'hidden'.
That's assuming the correct path is taken every time. If I didn't know where the white noise tool was, I wouldn't even think to check the settings for a noise generator. But if I did, it would go
Settings then Sounds & Haptics. 16 options, none seem to match. Maybe "personalized spatial audio?" Oh no,that's saying I need special headphones.
OK it's not under Sounds. Maybe it's in the Focus section? That's what I would use white noise for, focus. 6 options. Maybe it's under "Work Focus" or "Sleep Focus"? No.
General? 15 options, all with sub-menus but none seem relevant.
Control Center? Probably not... That seems safe to ignore. Except if I selected the "Hearing" option in Control Center settings, that actually gives me access to the background noise generator in control-center. But that doesn't seem obvious to me at all.
OK next is Display & Brightness and Home Screen. Probably safe to skip. Which then brings us to Accessibility. Again, it doesn't feel likely to me that it's in here, but no other choice in the settings feels correct, except maybe the Music app? Nope nothing there.
I check accessibility. I look past 18 options and see "Hearing" again, might as well tap that option. Even "Background Sounds" doesn't match what I'm looking for mentally, "White Noise". So it's likely my eyes miss it when I scan the list of options.
IMO it's an app. So make it an app, not an accessibility setting.
It's still hidden, just in a breadth of options instead of depth. A needle hidden in a 1 acre lot covered 1cm high in hay is more hidden than a needle in a 10 ft cube haystack.
There's a search tool, for all the menus, right at the top?
Have you ever used an iPhone as a day to day device?
A user manually checking every possible submenu to find what they are looking for would be quite an outlier. If they are that determined then I don't see what the issue is, since presumably they are then going to inspect them all anyways.
That cuts to how much of a mess spotify payouts are in general, where the subscription revenue pool is paid out based on global listens, and the people with fewer hours of use don't control which artists get most of their money. But as far as I'm aware the big labels don't like the idea of changing that.
