Loading is hard part of accessibility: you should clarify that loadings has been started, is loading and when ends.
Safari handles loading with vibration, 1 per secods and vibrate twice at the end of loading.
I did the development, by analogy with this framework - https://github.com/akaDuality/AccessibleLoading
This worked fine in iOS13 - iOS14, but from iOS15 until VoiceOver finishes speaking, CoreHaptic doesn't start.
In the release note, I did not find information