For help with EV Mileage Tracker:
Do not attach exported backups or include vehicle records, costs, or other sensitive information unless it is necessary to diagnose the problem.
No app account is required. On an eligible iOS reinstall, the app can offer to restore its latest private iCloud backup when one is available. You can also restore a full backup that you exported. Recovery depends on a successful backup and access to the same iCloud account or exported file; it is not guaranteed. If neither is available, removing the app can leave no recoverable copy of its local records. See the privacy policy for backup and deletion details.