Next, check the storage space usage of each application. The specific operation mode is to enter Settings >; General > usage > manage storage space, and then you can see which applications occupy the most space, and decide whether to manually clean up the cache or uninstall and reload.
If all else fails, you should back up the data and settings of your mobile phone to iCloud, restore the factory settings, and then restore the data from iCloud. This is a very useful method because iCloud does not back up "other" data. When the data is recovered, there should be no mysterious data in the mobile phone.