Other is directly related to what you’ve asked the device to do. Once in a while, Other gets that wrong and a back up, reset and reload, and backup restore can resolve that Other usage. But more often than not, the Other data usage is normal for what has been requested and it just rebuilds itself. A bottom-end iPhone storage model can tend to be “under-purchasing” for many, too.
Per Apple: 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.