I switch from an iPhone X to an iPhone 13 and the other system data fill the storage between two or more hours. I found many answers about that in two other posts: Other Storage Taking Too Much Space System Storage Full To solve this problem, I try: Load the iPhone X backup on another iPhone (the storage was smaller, but I don't observe the problem, the backup is safe). Clean installation of iOS 15.7, the storage was still filling, so I upgrade to iOS 16.0 but it didn't change anything. Disconnect and reconnect the iCloud account. From Photos, I switch the setting Optimise iPhone Storage to Download and Keep Originals, keep my iPhone unlocked in Photos and download all. Empty the cache of all applications. I try to retrieve some logs and the only one is a crash of an iCloud process. Downloading all the photos limited the time needed before the storage was full, but didn't stop the disk from filling. The problem seems to occur when the iCloud account is connected, and when photos or files are synchronise. In my case, a reboot frees the other system data. An option to limit the cache and preserve the system would be a good idea. If you want to consult the crash : cloudd 21-09-2022 13-33.crash