Is there anything I can do about this extremely vague block of data that’s taking up 30% of my phone’s storage? Mind you, this isn’t the operating system itself, as that’s listed as its own category.
EDIT: I tried (a) backing up to my computer, factory resetting, then restoring from backup and (b) setting the date years in the future. Neither worked, in fact (a) actually increased my system data to 34 GB! What DID end up working was updating my iOS from 18 to 26, which I had to do from my computer via iTunes since my phone was full. Apparently major system updates reset system data
That’s usually called “Virtual Memory” rather than “Storage”, as a well written app will take as much storage as it needs when first run, then manage cache size itself.