alt Hacker NewsNot sure if it was the same bug, but I had a storage issue where System Data ballooned to like 200GB.
It had the most bizarre solution; airplane mode, set time to one year in the future, reboot, wait a few minutes, set time to 6mo in the future, reboot, wait a few minutes, set time to now, reboot. Went from 200GB to like 15GB. Was ridiculous.
(For anyone looking at this and considering doing it, you also need to ensure iMessage retention is forever, otherwise the iPhone will think it's a year old and delete the messages)
Not sure why you're being downvoted, that was my exact issue. I only had a 128 GB iPhone 12 though and System Data had eaten up over 60 GB. As I cleared off more apps and data it would just eat up the excess.
The internet seems full of various wild fixes, but I could afford an upgrade so saved myself the hassle of futzing.