here is a post that explains what 'other' storage is
What is "Other" and What Can I Do… - Apple Community
Note that when you delete photos/videos they go to a 'Recently Deleted' album where they may be classified as 'other'. Try deleting them from there and see if 'other' storage drops.
Otherwise, if a forced restart doesn't clear up some 'other' data
Force restart iPhone - Apple Support
Unfortunately the only other way I've found that works is to backup your phone, reset to factory settings (erases your device), and restore from that backup
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