1)Restart your iPhone. This can sometimes fix minor software issues.
2)Reset Screen Time. This will erase all of your Screen Time data, including the inaccurate data about your Settings usage. To reset Screen Time, go to Settings > Screen Time > Reset Screen Time.
3)Update your iPhone to the latest version of iOS. Apple often releases updates that fix bugs, so updating your iPhone may fix the issue with your Screen Time data. To update your iPhone, go to Settings > General > Software Update.
4)Contact Apple Support. If you have tried all of the above and the issue is still not fixed, you can contact Apple Support for help.