My system data storage is increasing way more than normal, I have over 100gb of system data which is not normal. Please what’s happening?

When you tap System Storage (iPhone Storage) what do you see? Other Storage?

Keep your iPhone updated to the latest iOS. As of now, it is iOS 15.0.2 for iPhone 6S and above.

• Other: Non-removable mobile assets, like Siri voices, fonts, dictionaries, non-removable logs and caches, Spotlight index, and system data, such as Keychain and CloudKit Database. Cached files can't be deleted by the system.
• System: Space taken by the operating system. This can vary based on your device and model.

About cached files in "Other"

Finder and iTunes categorize cached music, videos, and photos as Other instead of actual songs, videos, or photos. Cached files are created when you stream or view content like music, videos, and photos. When you stream music or video, that content is stored as cached files on your device so you can quickly access it again.

Your device automatically removes cached files and temporary files when your device needs more space.

If storage on your device differs from what you see in Finder or iTunes

Since Finder and iTunes categorize cached files as Other, reported usage for Music or Videos might differ. To view usage on your device, go to Settings > General > [Device] Storage.

If you want to delete the cached files from your device

Your device automatically deletes cached files and temporary files when it needs more space. You don't need to delete them yourself.

I had this same problem although 40GB on a fresh install on an iPhone X 64gb. I checked all apps, deleted iCloud, photos, etc etc etc. I was pulling my hair out reading the same thing. Clear your cache etc etc etc. Blah blah blah. I plugged it into my MacBook Pro and synced it with finder. Bam! That 40 GB disappeared. It must have been a bunch of bad/broken syncs or what not. Something Apple should know about but refuse to admit. Either way, give it a try and see if it helps. I will be using my Mac to do backups more to keep things cleared out. Obviously iCloud backup and photos backup causes issues in the file system. Hope that helps someone else.

Im on an iphone 7 and my storage increased by 70 gigs I don't know what to do my storage is about to be full and I don't want to do a factory reset. The system storage alone is 71.75 gigs right now.