To completely remove Cube, delete the app and delete your Apple Health data.
Please note that you can not be restore health data.
If you are using iOS 13 or below, select whether to keep your health data when deleting the app.
Please be careful not to delete it by mistake.
Please note that deleted data cannot be recovered.
You can restore your device from iCloud or iTunes backup, but you cannot restore only health care data.
Please migrate your datas using iPhone backup.
Please refer to Back up your Health data for how to backup.
If you use iTunes's backup, please check "Encrypt iPhone backup".
If you already purchased Premium, you can restore your purchase after installing the app on your new device.