I think iOS has this application caching issue. Apps seem to always be caching data to the storage, but there is no option to erase, or remove it as needed.

it does it for you, if your phone starts getting full you'll notice apps randomly switch icon and name to Clearing or something like that quite a bit.

the issue that ive found when i was troubleshooting clients phones for "where is all my storage" is that the system does not automatically remove cached files like music/ spotify offline etc.

i never have seen the clearing text on my iPhone, although i figured it would be automatic.

Wow, I remember when you had to do this yourself on your Apple, with x = fre(0).