I have a 16GB iphone 6s. I am constantly having storage issues because the 'system' uses 5.2GB and 'Other' uses 8.3GB. Almost all my apps are offloaded and the app using the most storage is at
450MB. Is there anything I can do to lower the amount of storage that 'other' is using?
iPhone 6, iOS 10
You can try this.. but if your details are correct and you are using iOS 10, then you may lose some apps.
Backup/Reset/Restore your device, review these links:
How to back up your iPhone, iPad, and iPod touch - Apple Support
Restore your iPhone, iPad, or iPod to factory settings - Apple Support
Restore your iPhone, iPad, or iPod touch from a backup - Apple Support
"Other" storage
