"System Data" in iOS consumes all free storage space
I have a 64GB iPhone XS on iOS 15.5. Recently my phone kept giving me "Storage is full" errors, so I went into "iPhone Storage" under "General" settings. Here I saw that the "System Data" entity was taking up 27 GB of space. I deleted some apps, music and other content to free up roughly 5GB of space. Instead of avoiding the "Storage is full" error, the "System Data" entity just went up to 32GB to consume that free space...
What exactly is this mysterious "System Data"? There is no information provided under iPhone Storage about what this is or how to delete it. I'm stuck with a brick of a phone at this point that can't even download images or emails because the storage is constantly sitting at 100% full.
Other than a full factory reset, what options do I have to fix this? I do not want to nuke all personal data on my phone to fix this error. That is not a solution; it's a band aid for what seems to be a horrific iOS bug that needs to be fixed ASAP.
iPhone XS