Hello and welcome to Apple Support Communities, earthstarr7!
We understand you're seeing a high storage amount for System Data. We'd be happy to provide information about this.
Based on the information here, the amount of storage used by this category varies by device:
How to check the storage on your iPhone, iPad, and iPod touch
Content categories
The used content on your device is divided in these categories:
Apps: Installed apps and their content, and content stored in "On My iPhone/iPad/iPod touch" directory in the Files app, and Safari downloads
Photos: Photos and videos stored in the Photos app
Media: Music, videos, podcasts, ringtones, artwork, and Voice Memos
Mail: Emails and their attachments
Apple Books: Books and PDFs in the Books app
Messages: Messages and their attachments
iCloud Drive: iCloud Drive content that has been downloaded locally to your device. This content can't be automatically deleted.
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.
Have a great day!