Somehow (by transferring files?) I broke my KOReader on Amazon Kindle Paperwhite PW5. All I want now is reset all settings to default (factory reset?). For now, my KOReader doesn't want to start at all, so I can't change any settings.

All I can see is storage, but when i click somewhere — KOReader just shut down.
Please, help me to reset my KOreader to default settings (maybe I need to delete some cache files in KO folder? specific settings file?)
Thanks for helping, and sorry for bad language.